Quick Travel costs are ridiculous. I believe one of the biggest drivers of this inflation nonsense is allowing players to resell things they purchasse off the cartel market on the GTN (we all know you guys wont stop that because that's your $$$$). I'm not wealthy credits wise by any means but there are things you can besides punishing low level players quick traveling. Punishing players for things Bioware allowed to happen (bug exploits and Cartel Market sales on GTN) is only going to hurt the game. Bad move.
I personally know people who did the companion gifts expoit (one i didnt participate in) who were never punished or had their credits/gifts taken away. Some even laundered it in the GTN. I remember feeling bad that I didn't exploit sinced they were never penalized. No matter your opinion on the exploit, Bioware screwed it up completely. The blame isn't solely on the exploiters.
I don't have any suggestions except for making some fabulous strong hold decoration items that costs billions of credits. Maybe that will reduce credits in the game. Making it harder to make money is only punishing towards players who didn't exploit or are new to the game. Un do this while you can.