There are a plethora of markers out there in the price range you listed and it's truly best to do your own research. For starters, the Phantom performs well, as do Snipers, P68's, Illusions...
PBNation: A land of AGG Twib's trying to express their ability to pwn, genocidal idiots advocating their bloody ideals, extremists of every persuasion, and flamers stoking the coals.
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