I'm not giving anyone any info if they are planning on using a pump gun as a backup...buy a talon or a sabre.
Just kidding. You might be able to get a used Trracer(SP?) or Phantom off of Ebay or CraigsList.com for pretty cheap. You're just gonna have to look around. I bought my Phantom new from wevopaintball.com because I couldn't find one I liked used.
Pump Setup: CCI Phantom VSC, Silver with Blue Acrylic, Dye Sticky 3, Undercocking Kit, Red Dot Sight
Coming Soon: Homemade T-Stock, 14" Freak Barrel
Speedball Setup: PMR SE '08, Empire B w/ Rip Drive, 48/3000 Pure Energy
Looking for a CF tank...PM me
Trracers/Mavericks (same gun, different distributer), and Hornets/Tagmasters can be found very affordably on ebay just about anytime. $80 or less with out much fuss. Good, solid, reliable, though finding aftermarket barrels can be tricky (stock barrel ain't nothing special).
Old Kingman Hammers can be found for a similar low price. They can take more common spyder threaded barrels (fitting them through the pump handle is another story). I just scored one off ebay, give me a few weeks and I'll be able to tell you more about them.
A lot of people (including myself) are fans of the old sheridan pumps. Most can be found for under $100 (with the exception of the wood stocked models, which can go from $400-$900). Brass bodys and barrels, so they have a very solid feel.
Lightning Pumps, i got 1 for about $80 but you have to get a new pump kit for it cause the stock 1 breaks easily... CCM Economy Kit... ftw plus thats about under or around your price range... plus its super small, for tight playing.
LionsStatus and Canadian Drift, hot for o9