Question

Is it suitable/semantic to use <th> tag for column headers. I.e. should Price, and Qty be in <th> tags for table like this?

+-------+--------+---------+--------+
|       | apples | oranges | lemons |
|-------+--------+---------+--------|
| Price | 100    | 200     | 300    |
|-------+--------+---------+--------|
| Qty   | 10     | 10      | 10     |
+-------+--------+---------+--------+

Answer 1

Is it suitable/semantic to use tag for column headers.

Yes

I.e. should Price, and Qty be in tags for table like this?

Those are row headings, but still, yes.

<table>
    <tbody>
        <tr>
            <td>
            <td scope="col">apples <!-- both heading and data so use td with scope -->
        <!-- etc etc -->
            <th scope="row">Price