That depends on how long you consider the long run to be. You have to have plastisol, containers, a way to heat it, colorant, glitter, heat stabilizer, good gloves, maybe softener and hardener, and at least one mold.
If you go on the cheap maybe you can start for less than $200. Figure the retail cost of your bait and see how many you need to make just to break even. When I added tube making I had $300 in the first one. With what I paid for them I think I broke even at 1,000.
I don’t know if I have ever saved any money but I keep making baits because I love it.