Its almost all empty shells, so you would have to buy mods... there are a couple that have mods in them but the point of the cartel market is mostly for cosmetic upgrades. Also, you dont need to buy empty shells (orange gear) from the cartel market, there is plenty on the GTN.
I would suggest you do not buy anything for a few weeks so that you can play some and get reacquainted with the game. If and when you do decided to buy coins, go with the 5500 for 39.99... its the best deal.