There were a few times I went over my budget since I had bid on 3 players at the same time and won all three.

Sure it screwed up a few things, but I had cup matches to help me cover some debts and in the end I sold a lesser player.

Obviously, being in debt virtually and in real life is not a good thing. Cover your losses and move on

You should always ask yourself

1. "If I win this, I'd be -XXmil in debt. What would happen then?"
2. "Would my cup/cl matches cover my debt?"
3. "Would I have to sell players to keep this expensive one? Is it really worth it?"