Denial

Is there an emulator for Iphone or Ipad, or a compiler that would turn a .prg to something sellable on the apple store?

I assume you want to compile your prg and the emulator into a Vic20 that autoruns your game so the answer is no because you would be selling the emulator code which is not yours to sell.

Apple also restricts what apps can be sold, they have to be "safe"

You might be better off looking into Google's app maker to start with though I don't think you can sell these apps either.

It is object based and can manipulate graphics e.g. whack a mole is possible very easily.