Dixie moulds from Dixie Gun Works are pretty cheap! But they have no sprue cutter, so you have to cut the sprue off by hand. I use a set of nail-nippers, but some people use their hunting knife, just like the Mounain Men did!

Lee RB moulds are inexpensive and make good balls.

Get the mould very hot so there are no "wrinkles" in the exterior surface of the ball. The biggest plroblem is with voids in the casting. Keep the ladle spout on the pouring hole for several seconds (length of time depends on the size of the ball) as the cooling casting is shrinking to let molten lead flow into the potential internal voids. I have had as good accuracy with cast balls as with swaged ones, if cast well.

ALSO, for balls and ML bullets, use ONLY PURE, DEAD SOFT LEAD! Using any other, harder alloy will make it difficult or impossible to load the rifle, particularly after the bore picks up some fouling.