Small talk on upgrading 120 gallon reef.

So me and my parents were having small talk on upgrading my 120 gallon. Me being 16 and loving anything fish related now wants to upgrade (though my parents may not see that happening yet :p). I mentioned a 200 gallon I saw on Craigslist that came with a stand and a few other things. It was listed for $250. That's a pretty good deal IMO, but my mom said that didn't seem big enough to make an upgrade worth it......... :nuts: :nuts: :nuts: My mom should know not to say things like that around me by now :rolleyes: My parents where saying that double the tank size I have would be good, and the bigger the better for me :p The only problem is finding the tank size I am looking for, for a good deal. I have looked through Craigslist and there is never really any large tanks for sale that are not a fortune. By large I mean I mean like 200+, and by cheap I mean no more then $500, but I don't know if that's possible money wise. So I am wondering if anyone is looking on selling their largish tank that isn't to expensive. What I am looking for in a setup is the tank/stand, maybe sump and skimmer if you have it, and maybe lights. No complete setups please. Obviously, the less there is the cheaper it is for me and more custom I could get. Is my price range for a Craigslisttank realistic even? And if no one one is selling a tank does anybody know where I could look? The cheaper price is how I could sell it for my parents. Well, that and I may ask about getting a job at my LFS for a while lol. Anyway, thanks :)