First, congratulations on your decision to start drilling your own equipment! Before I returned to bowling about five years ago, I did the same. I was not mad at anybody. I was just expecting to drill a lot of new equipment for myself, and I wanted to experiment with different grips and layouts. Since then, I have easily drilled over 50 balls, some multiple times. It has given me great satisfaction and confidence to know that all of my equipment is exactly the way I want it. I learned a a lot, and saved a few bucks, too.
I was fortunate to find a used bowling ball jig on eBay for $300, and a new commercial-quality drill press at Lowe's for around $300, and a few used drill bits for another $100. That was enough to get me started. The most expensive additions to my do-it-yourself Pro Shop
were a Kaufmann scale ($1,000) and rejuvenator oven ($2,000+). My strategy was to use money won in league brackets, high game pots, tournaments, etc., to fund my enterprise. That helped a lot.
My favorite suppliers are InnovativeBowling, BuddiesProShop, and CheapBowlingBalls. Innovative has plug and the color kit and all the drilling equipment and other supplies you may need including a yellow pencil. The others have good prices on balls and inserts.
Here is a tip to save all those plastic balls that crack around the holes. Try crazy glue (cyanoacrylate) and accelerator spray (from your local hobby shop).
I wish you the best of luck, and years of enjoyment drilling your own equipment.