Abilities, from what I saw, cost 1 credit. And since you can only buy 1 ability every time you lvl up, this makes sense. Clothes I think are obtained by completing Challenges. I don't know if if there is another way to obtain weapons, attachments, and character customization items, besides Challenges.
I like that,I just hope it isn't something like "do 9 headshots in 9 shots then jump off a ......etc." I like a challenge but those stupid ones do piss me off. :swear: Btw Horse did you join Unit 13? I saw you on their forums.