add the values in a list and display total price react js

First, in the map of tray items you can multiple the quantity and price for the total

change this
<th>0</th>

to this 
<th>{ele.quantity * ele.price}</th>

As for displaying the total amount for each item, you need to create a function that will add all the items price * quantity. Here's sample function and implementation for your reference.

  const handleTotal = () => {
      // reduce will add all of your price and set a default value in case the items is empty
      return trayItems.reduce(
        (acc, curr) => Number(acc) + (curr.quantity * Number(curr.price)),0
      );
    }

then you need to change this 

<h3> total amount 0</h3>

to this

<h3>{`total amount ${handleTotal()}}</h3>

For removing the item if the quantity is 0, first, you need to modify your decrement function so that it will allow to make the quantity 0

const decre = (idd) => {
    settrayItems(
      trayItems.map((stat) =>
        stat.user_id === idd
          ? {
              ...stat,
              quantity:
                stat.quantity !== 1 ? stat.quantity - 1 : (stat.quantity = 0)
            }
          : stat
      )
    );
  };

Then add a checker that will show if the quantity is greater than 0

{trayItems &&
                trayItems.map((ele, index) => {
                  if (ele.quantity > 0) {
                    return (
                      <tr key={index}>
                        <td>{ele.item}</td>
                        <td>{ele.price}</td>

                        <td>{ele.quantity}</td>
                        <th>0</th>
                        <td>
                          <button onClick={() => incre(ele.user_id)}>+</button>
                          <button onClick={() => decre(ele.user_id)}>-</button>
                        </td>
                      </tr>
                    );
                  }
                })}

To re add the item again in the tray you need to modify the handleCheckClick so that if the trayItem.quantity is equal to 0 it will add 1 to it.

const handleCheckClick = (ele) => {
    const dupe = trayItems.find((obj) => obj.user_id === ele.user_id);
    settrayItems(
      dupe
        ? trayItems.map((item) => {
            if (item.quantity > 0) return item;
            return {
              ...item,
              quantity: item.quantity + 1
            };
          })
        : [...trayItems, { ...ele, quantity: (ele.quantity = 1) }]
    );
  };

First of all, clean your data. Always make sure your data is in a good state before using it.

I added a filtering in your decre function. This will filter out items with no quantity (also, I'm doing the mapping on the "previous state").

A new state is added (total). The value is updated every time the trayItems state is updated (useEffect).

However, I would suggest you to use a reducer instead.

Codesandbox: https://codesandbox.io/s/goofy-chatelet-d9oe8f?file=/src/dashbord.jsx

I tried your code and also solved it can you check it if you want exactly like this or anything different:

import { Fragment, useEffect, useState } from "react";
import "./styles.css";

const item = [
  {
    user_id: 1,
    item: "biriani",
    price: "50",
    selling_price: "60",
    created_at: "2022-08-29T10:12:58.000000Z",
    updated_at: "2022-09-15T14:05:45.000000Z",
    tax: "5%",
    total_price: "80",
    status: 0,
    quantity: 0
  },
  {
    user_id: 5,
    item: "alfarm",
    price: "100",
    selling_price: "120",
    created_at: "2022-09-07T11:06:23.000000Z",
    updated_at: "2022-09-07T11:06:23.000000Z",
    tax: "5%",
    total_price: "140",
    status: 0,
    quantity: 0
  },
  {
    user_id: 4,
    item: "burger",
    price: "80",
    selling_price: "80",
    created_at: "2022-08-29T10:21:13.000000Z",
    updated_at: "2022-09-14T04:46:36.000000Z",
    tax: "5%",
    total_price: "100",
    status: 0,
    quantity: 0
  },
  {
    user_id: 8,
    item: "sandwich",
    price: "100",
    selling_price: "120",
    created_at: "2022-09-07T13:27:33.000000Z",
    updated_at: "2022-09-14T04:46:37.000000Z",
    tax: "5",
    total_price: "140",
    status: 0,
    quantity: 0
  },
  {
    user_id: 9,
    item: "pizza",
    price: "200",
    selling_price: "220",
    created_at: "2022-09-07T13:27:33.000000Z",
    updated_at: "2022-09-07T13:27:33.000000Z",
    tax: "5",
    total_price: "240",
    status: 0,
    quantity: 0
  },
  {
    user_id: 10,
    item: "chicken sadwich",
    price: "200",
    selling_price: "220",
    created_at: "2022-09-07T13:27:33.000000Z",
    updated_at: "2022-09-07T13:27:33.000000Z",
    tax: "5",
    total_price: "250",
    status: 0,
    quantity: 0
  },
  {
    user_id: 11,
    item: "sharja shake",
    price: "60",
    selling_price: "70",
    created_at: "2022-09-09T06:58:45.000000Z",
    updated_at: "2022-09-15T14:05:53.000000Z",
    tax: "5%",
    total_price: "80",
    status: 0,
    quantity: 0
  },

  {
    user_id: 1,
    item: "biriani",
    price: "50",
    selling_price: "60",
    created_at: "2022-08-29T10:12:58.000000Z",
    updated_at: "2022-09-15T06:17:20.000000Z",
    tax: "5%",
    total_price: "80",
    status: 1,
    quantity: 0
  },
  {
    user_id: 5,
    item: "alfarm",
    price: "100",
    selling_price: "120",
    created_at: "2022-09-07T11:06:23.000000Z",
    updated_at: "2022-09-07T11:06:23.000000Z",
    tax: "5%",
    total_price: "140",
    status: 0,
    quantity: 0
  }
];

export default function App() {
  const [trayItems, settrayItems] = useState([]);
  const [totalAmount, setTotalAmount] = useState(0);
  console.log(trayItems);

  const handleCheckClick = (ele) => {
    const dupe = trayItems.find((obj) => obj.user_id === ele.user_id);
    settrayItems(
      dupe
        ? trayItems
        : [...trayItems, { ...ele, quantity: (ele.quantity = 1) }]
    );
  };

  const incre = (idd) => {
    settrayItems(
      trayItems.map((stat) =>
        stat.user_id === idd ? { ...stat, quantity: stat.quantity + 1 } : stat
      )
    );
  
  };

  const decre = (idd) => {
    settrayItems(
      trayItems.map((stat) =>
        stat.user_id === idd
          ? {
              ...stat,
              quantity:
                stat.quantity !== 1 ? stat.quantity - 1 : (stat.quantity = 1)
            }
          : stat
      )
    );
    
  };

  useEffect(() => {
    let tt = trayItems.reduce((accumulator, object) => {
      return accumulator + (Number(object.price) * object.quantity);
    }, 0);
    setTotalAmount(tt);
  }, [trayItems]); // just calculate the amount based on item and quantity

  function Tray({ trayItems }) {
    return (
      <>
        <div className="foo">
          <table>
            <tbody>
              <tr>
                <th>item</th> <th>price</th> <th>qty</th> <th>total_price</th>
              </tr>
              {trayItems &&
                trayItems.map((ele, index) => {
                  return (
                    <tr key={index}>
                      <td>{ele.item}</td>
                      <td>{ele.price}</td>

                      <td>{ele.quantity}</td>
                      <th>0</th>
                      <td>
                        <button onClick={() => incre(ele.user_id)}>+</button>
                        <button onClick={() => decre(ele.user_id)}>-</button>
                      </td>
                    </tr>
                  );
                })}
            </tbody>
          </table>
        </div>
      </>
    );
  }

  return (
    <>
      <div>
        {item &&
          item
            .filter((person) => person.status === 0)
            .map((ele, index) => {
              return (
                <div
                  style={{ cursor: "pointer", border: "1px solid black" }}
                  key={index}
                  className="newmo-card"
                  onClick={() => handleCheckClick(ele)}
                >
                  {`${ele.item}`}
                  <br />
                  <br />
                  <span> {`${ele.total_price}`}</span>
                </div>
              );
            })}
      </div>
      <Tray trayItems={trayItems} />
      <h3> total amount {totalAmount}</h3>
    </>
  );
}