This website has me thinking...

Scratch? As in your own shells? Pretty difficult. As in using Keller shells? Pretty easy. Just takes a couple hours of researching/ordering parts online and putting it all together. Having a layout mat, like the one from Drum Foundry helps a ton. I prefer to wrap as opposed to staining/poly or oil/poly. It's more durable even though it costs a few bucks more.

The most expensive tooling you'll buy is the stuff needed to cut your own bearing edges. And it's the best thing you'll do. All you need is a router that can be bolted to a table insert plate, a router table insert plate, and router bit(s). You make a solid top for the router and plate, and set it on two saw horses. Make it big enough to do bass drums on. So once you've made it, you can pull it out to make more again and again... Snares, kits, re-wraps, re-cuts, etc... And it's not difficult to learn to cut them. Just buy some shell cut offs from the supply houses. They'll sell them to you cheap. Practice on those. There are good tutorials for cutting edges on Drum Foundry too.