I’m currently looking for an affordable 3D printer for Lost Wax casting.
Check out the rep rap builds. There are several online where you simply purchase what you need (extruder, motors, etc.) and assemble. Kits are between $800 and $1500.
There is a gentleman on youtube who did exactly what you are talking about, but he used PLA (poly lactic acid plastic) printed by the printer. Then he followed the usual aluminum casting methods, which I assume are different from the lost wax process. And he had great (the part worked in his machine) results.
I can point you to several websites if that helps.