Disregard the prices as this is from a renowned lfs in my area, but should give you some ideas and potential cost. Aquabid is a good research for ideas for what you want to put in your tank.
Geophagus, abalios WILD Colombia, , 2-2.5", $7.00 ,
Geophagus, brasiliensis, , 2", $5.00 , 6 for $27.00
Geophagus, brachybranchus "Surinamensis Guyana" WILD, , 1.5", $8.00 , 6 for $42.00
Geophagus, crassilabris "Tank Raised", , 1", $20.00 , SIX ONLY
Geophagus, sp. "Tapajos II", , 1.25", $8.00 , FEW
Geophagus, sp. "Red Head Tapajos" , , .75", $8.00 , 6 for $42.00
Geophagus, sp. "Rio Pindare", , 1.5", $7.00 , 2 ONLY
Geophagus, steindachneri "Red Hump" WILD Colombia, , 2", $7.00 ,
Geophagus, taeniopareius WILD Colombia RARE, , 1.5"+, $20.00