My record is 19, and that was a free transfer, worth 600K (I was level 1, so it was a decent amount of cash)
Seemed a good idea, until the other guy wouldn't back down and I was bidding purely for pride, and the fact I didn't want to waste that many tokens and get no return.
This season is crazy, I'm seeing average players go for 30+ tokens now, I only buy scouts now, guaranteed return, great players.
I don't buy any over the age of 22 though, 23 at a push if they're really good.