Is there an undo if I apply the wrong bulk price change?

There's no undo button, so check before you apply:

1. Click Preview first. It shows how many products and variations would change and a before and after table, and nothing is saved yet.
2. Apply Price Update asks you to confirm and names the scope, for example "ALL products".

If a change goes wrong, run another update to correct it. Be careful with percentages: a 10% increase followed by a 10% decrease does not give back the original price. For a fixed list, Set to a fixed price may be easier.

The Activity Log at the bottom records each preview and apply in your browser.