In Star Wars A New Hope Han told Chewie he intended to use the credits he got off the old man to repay his debt. We see in the additional scenes a negotiation with Jabba that he would pay up following this last shipment seeing how Jabba sent more enforcers out to get Han & Chewie this time Bounty Hunters are we to infer that no Han was going to keep the credits. I reckon he was going to use the credits to get far from Jabba and then bribe any bounty hunter that would go looking for him. Joining the Rebel Alliance was just a big distraction and he was never really serious about fighting the Empire when he was already wanted criminal like so many other denizens of the Galaxy. The Rebels on the other hand were politicians and Han & Chewie merely hung around with them until he could gather enough credits. Han was never going to pay Jabba though he knew his life as a smuggler was over but seeing as Jabba had already double crossed him it was safer to lie to him and start a new life perhaps in and around Kessel flying through the Galaxy and stopping off on the occasional planet or moon.