I don't know what the solution is here.

One of my sites enjoys a ridiculous number of fraudsters trying to make purchases, many - but very much not all - from the tor network.

The easy solution is to punish everyone and ban tor exit nodes from access, and woo, a significant reduction in my fraud rate.

The way I justify this to myself is that the site only accepts payment via PayPal and/or credit cards, and paying with those in itself gives up a good amount of privacy.

For sites that don't make a profit and have to use unpaid time to clean up the mess from some tor nodes, I really don't know what the solution is.

It definitely sucks for legitimate users.

Edit: one more difficulty is that I don't know if I was targeted by one or two lazy-yet-determined fraudsters who only use tor, and so make tor look worse than it is with their repeated attempts. No idea even where to begin with that one.