If you're buying filters I would seriously check out
http://hvstar.net/ . The place used to be called MaxSaver and even though they look sketchy, I assure you that it's not and lots of other photographers can attest to it. Prices are definitely cheaper and they ship directly from Hong Kong.
Quality makes a difference in any glass you get, whether it be filters to teleconverters to lenses.
For a simple clear UV filter Hoya makes some good ones. The Pro1 and SHMC ones are great. They should not be that expensive on MaxSaver.
For a Circular Polarizer (CPL), I would go for ones with brass rings and thin (1mm) glass. The thin glass is to avoid any possible vignetting and the brass rings is to avoid having the filter get stuck on your lens, which is very easy to do with aluminum rings.
I would also get filters in diameters as large as the largest diameter lens you plan to get. So if you have lenses with filter diameters of 55mm, 58mm, and plan to get a lens at 77mm, get one filter at 77mm and then buy cheap step down rings for the 55mm and 58mm lenses. This saves you the cost of buying three separate filters at 55mm, 58mm, and 77mm.