Used SL-68 with up:ed barrel and a springkit (beats the s**t outa the semis for fun, economy and skill improvment)
or
Used phantom w. CA 7 or 9 oz. and spring kit (might be slightly over your 100USD)
or (my favourite if U can find it, most certanly over your budget but a Whooping Woodsball marker) Sterling STP w CA & Springkit and armson barrel (My set up
so I might B slightly partial)