I've used practice paint balls from www.xtremez.com
and thy work like a charm with all spyders. How do I know?, you ask?
I owned all spyder gun types from pump to the E markers =P
The only gun yet is MR1 WHICH I want badly
Well practice paint and
'seconds paintball' from www.actionvillage.com
are also good for just messing around with friends. No ball breakage what so ever, EXCEPT, contridictary, a few may be broken when you buy the box, sadly.
XTREMEZ PRAC. PAINT - $20.00 USD
ACTION VILLAGE SECONDS PAINT - $25.00 USD