A GREAT gun for the price, likely the best you'll find under $50. But I wouldn't recommend it if you want it to use in any game where you'll be at a bit of a range (30'+) when you make your shots.
http://www.airsoftgi.com/product_info.php?cPath=139_181&products_id=2914
Good gun, bit a bit overpriced:
http://www.airsoftgi.com/product_info.php?cPath=139_181&products_id=2434
3-BB Firing, well built, good buy:
http://www.airsoftgi.com/product_info.php?cPath=139_181&products_id=3133
Additional shells:
http://leapers.com/pages/airsoft_sport/airsoft_equipment_mag_m3_6_c.htm
All of them are also available in pistol grip version, without the full stock. You'll be trading weight and manoeuvrability for accuracy and stability.