Would VCs consider a site sold on auction to be a proven founder?

I have sold a website of mine on Flippa for high five figures. Would that work in my favor when trying to raise money for a startup idea? Or is that too small to even matter and not worth mentioning?

It counts, but you must expect an angel is nobody's fool. They will look as closely as a bank for proof. You have to show them cancelled checks or lawyer's contracts to prove an ams-length sale. A screenshot of a PayPal transaction might not cut it. Bank statements showing the revenue would help too.

VCs aren't going to be interesting unless you're operating at multiple millions with the ability to bring back 10 to 50x what they put in. If you're already operating at multiple millions, your five figure exit isn't going to make much difference.

For "high five figures", an Angel is more likely to ask you why you're not investing your own money into your new thing.

If you are (investing your own money), then the sale of a previous idea isn't going to be as interesting as the fact you're putting your own "high five figures" and time into a new thing, so you have significant risk in the game as well as them.

In either case, the exit sale might help a little, although it might also raise questions - why did you sell out, what could you have done differently to scale it further etc.