Disclaimer: this is from memory

You could submit paid products to default Cydia repositories, where you personally handled payments. There was no commission in such scenarios. If you opted for payments to be handled by SaurikIT, a 30% fee was in place.

Cydia had special deals in place for Intelliborn products, I dont think this extended to other groups. Intelliborn previously operated Rock Your iPhone, which was acquired by Cydia and this was a negotiated term.