For many years I've been trying to have a good idea, this may be it.
Ok, so you want to have a successful Part 15 business of some kind. Try this:
Order and build an AMT5000 from sstran.com, the most efficient Part 15 AM transmitter ever designed.
Step 2 contract with a a qualified engineering firm to conduct certification measurements for application to the FCC.
Step 3, as a Certified AMT5000 Builder, seek orders from people who want ready-built versions of the AMT5000.
Step 4, use the in-rush of profits to fund your Part 15 radio station.
Step 5, live happily ever after.
What could go wrong?