i bought a young adult male ridgey for 80 bucks,but your looking at at least 100 for the cheapest monitor,ridgeys or storrs into the thousands for rarer ones,1200 odd each for mangrove juvies to 2200 usually for perentie juvies to even higher prices for others,like all reptiles,there worth as much asomeones willing to pay,another thing u reallyt need to consider is the cost of feeding them,monitors eat heaps,heaps and heaps,they have extremely high metabolisms