Try E-paintball.com, ANSgear.com, and the spyder official site.
I'd sell a new one for at least $110.00 but used at least $70.00-80.00
Spyder Pilot ACS is a good gun for Under $100 avilable @ Wal Mart and online
That is directly dependant on the type of marker you're using, and just how trigger happy you really are... I've got a Spyder Pilot ACS, and when playing at either semi or 3-burst intervals, 500 paintballs usually last me an entire day, depending on the skill of the competition.
you can take the Venturi (star looking piece) out of the bolt with low profile needle nose pliers check http://www.ottersccustoms.com/boltmod.html if you have a rear cocking bolt check http://www.ottersccustoms.com/rear-bolt.html this is a very cheap way to make a ACS bolt the bolts shown are Spyder
Grupo ACS was created in 1997.
ACS Nano was created in 2007.
ACS Recaş was created in 1917.
Gabor Acs was born in 1926.
Grupo ACS's population is 138,540.