TL;DR your prices aren't too high, they are too low and you don't need the business from people who think otherwise. This is not your job, this is you providing skilled labor for something you love. Too much of this BS will kill that love and you will go away. We've already lost enough people with the Amiga and technical skills needed. I don't want to lose you too because jerks take advantage of you and steal your love for us and this platform.
OK, now for the long version
Honestly, I think that your prices are too low. Really I do. Factoring parts and labor (and headaches from belly aching, ignorant, cheap a$$ owners) I think that you're losing money on every job. If someone isn't willing to pay what a job is truly worth including the benefits of a repairman who does quality work, is knowledgeable about the application (knows how to diagnose, perform work on and test after on an Amiga and not just a radio shop repairman who knows nothing about the application but just replaces caps and hands it back without proper diagnosis and testing to validate the work), and is conscientious they can just do it themselves or find some hack who will do a cheap, but crap, repair job.
You have skills that must be respected and compensated for. Take a recap. If after buying quality components you have $25 left in the budget, you're losing money. An average recap takes what at least an hour if done properly - clean board, diagnose, repair, test and clean at least - your time is worth more than $25 an hour. I don't know a reputable shop charging less than $50 an hour plus a minimum bench fee.
Forget about the quality of your work for a minute and just look at the economics of sending work to Europe. To send work to Europe from the US is ridiculously exorbitant if you want to ensure that everything gets there and back safely. Shipping is ungodly, properly declaring can result in customs and taxes far exceeding the cost of repair - in BOTH directions. Unless the owner is willing pay through the nose for a fast carrier like FedEx, UPS or DHL, transit time alone is going to be on the order of a month. Add possible delays in customs.
Don't forget to pay for insurance! I've had enough packages that didn't survive the boat trip well. Of course the problem with an insurance claim is that even if you (somehow) receive full insured value refunded, the owner still loses. He may have his money back, but how much is he going to have to spend to buy a replacement Amiga item and then to start the whole process all over again. Perish the thought of it being one of the many expensive or difficult to find items.
Oh, there's also the god awful fees that PayPal charges for currency exchange and foreign fees. Recently the fees for some European countries has increased to as much as 10%!
Of course it doesn't help when people intentionally screw you. For example when you offered to build the monitor switches and people committed to paying you for them then backed out after you had already paid for the parts. That is just unforgivable. Not just trying to get your work for less than cost, but to lie to you. Paying for the parts up front without them paying you back could have been the difference between you being able to put food on the table or not. THAT, in my opinion, is heinous. For me, those people would be on a permanent black list. They would be publicly shamed. Actually they sort of were because they are listed in the thread as committing then welching
Yes, this kind of behavior just ticks me off. Milder than I'd like to say it but this is a family friendly place

Grrrr :angry:
DON'T sell yourself short. You are SKILLED labor, not SLAVE labor. People who want good work recognize this and will pay accordingly. Those who don't, are never going to pay what the work is truly worth and it's not worth your time and sanity to chase that kind of customer or to try and placate them with discounts that lose you money.
This is a seller's market, not a buyer's market. How many repair shops in the US can replace capacitors? Lots. How many can do that with the knowledge and tools applicable to Amigas? I believe that I can count them on less than one hand.
Charge the real cost of parts including shipping and handling (yours! - you have to spend a lot of time researching and sourcing proper parts) and a reasonable markup (don't expect me to quantify that - I have no idea what constitutes "reasonable" although I can identify grossly unreasonable). Charge a fair price for your labor. $25 an hour is NOT reasonable, it is too low. In my opinion much too low.
If someone isn't willing to pay you that fair price, they aren't work that you need. There's no reason for you to knock yourself out for an ungrateful skin flint.There are plenty of people wanting good work, recognize the value of good work and will gladly pay you that fair price.
If all this garbage and all these jerks drive you to leave in disgust, I can understand it. There's some awfully ungrateful Amiga owners out there.
I HOPE that this doesn't drive you away but you MUST do what is right and necessary for you. You have, and hopefully will be able to continue to, provided much for this community and if you are not able to continue, that is the way it must be. Plus you would get the satisfaction of seeing those jerks pay through the nose for something that they could have gotten done better and for less if they had properly appreciated you in the first place. Either way, I personally will respect your decision and thank you for what you have done for the community.