You can get stuff of the GTN as mentioned before.
Even the 1M things aren't out of reach with the help of a subscriber.
Got a 1M Artifact unlock for my entire account, using a subber helping me than sending COD mails of 350, 350 and 300 (yes, I am a pref. player).
So if you got some great friends who are sub, you can use that to get around the limitations without needing the cartel coins (1800 IIRC for the item I just mentioned, that's over $30)...
Buying the game should be around $13-15. It's basically only a month sub, nothing more nothing less. If you pay more than that you're getting robbed (well unless for those VIP-extras of course)...