I can recommend Sunfire Testing for certification. They are used to working with hackers.
If you want you can email me and I can maybe help with you with some advice.
The price was reasonable (for what it is), the main contact was great, they were very fast and super flexible with our delays.
I know they offer CE, but we just went for FCC on unintentional emitters. It wasn't nearly as challenging as we thought it would be.
Expect to pay something around $2,500 to $5,000 depending on how labor intensive your tests are, or become.
Yeah, that's what's discouraging. For something that is effectively a hobby project, spending many thousands of dollars is too much of a risk, when you're not even sure people will buy the thing you created.
FWIW, I've done some digging and at least it's not just a mafia shakedown (like the USB-IF charging thousands for an artificially scarce numeral).
The equipment and expertise are both expensive and time consuming. DIY is possible, but would cost considerably more.
I'm a little surprised I haven't heard about a single start-up accelerator that has cert gear available...
I'm curious to know what you found so that I don't have any unpleasant surprises should I go ahead with a hardware product! Maybe konschubert also has experiences they could share here.
This is the thing that got me down and it seems to be the biggest barrier to entry for commercializing hardware products. The CE/FCC certification is killer.