My Nemco wire cutter works great. I don't see a need for heated wire. Personally, I don't want my cheeses looking like cubes. Doesn't fit my marketing goals.
Investment is not your first concern. Step 1 - contact Florida's Milk Safety Division, Department of Agriculture, or whatever agency regulates cheese "manufacturing". My advise is don't sell ANY cheese before you are legal. You will just burn bridges and close doors. I spent 2-1/2 years learning to make good cheese before I got my license and didn't sell a piece, not even to friends. Give it away, do sampling parties, ask for honest feedback, and ask lots of questions here. Shoot for making the best quality that you can and the rest will follow.