You must spend it on something for yourself. Can’t payoff a debt or bill. Can’t spend it on someone else. Can’t donate it to charity, political cause, or someone else. Can’t use it as a down payment on something bigger.
To play along, I assume it needs to be a single item and you want a luxury thing, not “groceries”.
New TV. The HDMI ports on the current one don’t work. We have it hooked up with the fancy composite cables so we get high def, but it hitches on fast action and it’s harder to find things like Roku that don’t require HDMI these days. I can’t justify dropping $500 out of my own pocket just for that but since I need to spend yours…
Ooh, lucky me! Let’s see, that’s about £310. I think I’d get myself some new clothes and shoes. We’ve been on a bit of a budget lately and a lot of my current stuff is pretty worn out.