The most bang for the buck in servo land is the Hobbico CS-170. It costs a bit more than the popular HiTec 645MG, but the 645 is weak and prone to stripping. The CS170 is actually a HiTec HS5955TG, that has been re-branded with a Hobbico sticker. Price is under $90, which is nearly $30 less than you pay for the same servo with a HiTec sticker. This thing has 333oz of torque, and will swing your 2.2 tires around with some authority.
If there's one thing I try to tell people new to this, it's to buy the best servo you possibly can. There are a ton of other places you can save money and hide it, but an inferior servo will always remind you it's there every time you run the truck.
Not as good as the above mentioned but you can get by with a tower pro 945 and it's around $30 and I think a little better than a 965.?
But as todd said you notice it when you really need it. But when I get big I'll get a real strong one.