Every picture or video of a "shot maker" I've found online shows lead being dripped through an orifice and allowed to drop over a "bridge" before falling into a coolant that helps the shot solidify. This is basically a "shot tower." The process is very old, and while the current day machines look quite complex, it's still the same process. Depending on how the lead is poured, different sized pellets form and cool as they fall. The height is selected to control shot size and allow the pellets to cool sufficiently to remain fairly round when they hit. Any non-mold shot making process is a variation on this basic concept. The cost for these machines comes from the selection of the right materials and production of the parts so that the machine works. It's not a tinkerer's "easy project" by any means.
Perhaps you could buy shot in person and let the shop you buy from handle the rather high shipping costs. I do that with bullets almost all the time, and still manage to afford decent quantities.