Manufacturer is generally more important then the style. Generally all airsoft aeg's work the same so how it looks like outside is up to you. Though the advice in the Airsoft Newbie Buying Guide about styles is good. Generally ak47, m16/m4 or mp5 are good starter gun styles due to the availability of accessories and upgrades.
For $250, the best you could manage is Aftermath stuff. Both the Broxa (full stock MP5) and the Kraken (AK47) are decent bargain basement guns, about $160 or so each. Stay away from Aftermath's Kirenex or Knight (both M4 variants) and the Lycaon (collapsible stock MP5) though, not a good rep. The next better manufacturer would be JG and you won't get one of those cheaper then $300.
As the previous posters mentioned, if you're not 18 years old yet then you'll be unlikely to be able to find a place that will sell you a gun. And even if you do, pretty much all playing fields are restricted to 18+ as well.
You're better off saving your money and getting a good gun down the road. While you're waiting, buy the unrestricted stuff you need so you'll be ready. Stuff like Camo, web gear, slings, holsters, goggles, boots and such. then when you reach 18 (or have saved up enough money if you're already 18) you can get a decent gun ($400-$600) and be ready to play.