I made a topper mod for Terminator 2 and am selling it here on Pinside. I had to think a lot about the price to offer it at. The reality is that if the same topper that I'm selling were made in china in large numbers, it could be made significantly cheaper. I'm not very confident I could actually SELL large quantities of a mod for a 25 year old model of a niche hobby.
Aside from pay for the parts (led's, wires, lamp sockets, special connectors, etc.), stock sheet metal and the machining time of the metal, stock acrylic and machine time laser time cutting the acrylic backing, I pay for it in my personal time, designing, assembling, and testing the things.
I sell it at around $200 though, which i suspect OP wouldn't approve of.
All said and done, if I were to consider what I'm paid hourly for my day job (software engineer), i make far less on the topper than I do for the equivalent time spent making the toppers.
You're paying somebody because either it's not worth your time to do it, or they can do a better job of it than you believe you can on your own.
You aren't under any obligation to make a deal and pay them for their time. And the less time somebody has, the more valuable it is, and the more you are likely to be charged for their services. There isn't a factory or magical replicator that is churning these out without any personal cost to the creator. The last batch I produced, my house was a mess, with partially complete Toppers covering my dining room for weeks. I spent late nights stripping wires, soldering, bonding/clamping/waiting so I could bond/clamp/wait on another, then another. I had to interface with people and try and keep them up to date, answer their questions on PM, try to find them the best shipping prices, and then wait/follow up to make sure what they received wasn't broken or worse - a disappointment.
Considering everything that I put into making these things, if somebody offered me the same amount of money to take my free time and do something they wanted, I wouldn't do it. But I'm doing it here on pinside because I thought it would be neat to share something I hand made with the pinball community and enjoy the idea of these things being out there in pinball machines around the world. The thrill has worn off for me though, and after this last batch of sales closes tomorrow, I'm done making T2 Toppers. Thankfully I haven't had to deal with this sort of post insulting something I poured my best effort into doing right, because that would have really taken the wind out of my sails. Thankfully, everyone that received one has been extremely positive about it.
For anybody to publicly criticize, insult, demean, or shame someone who has done nothing more than offer their time to make something you apparently desire and that you went as far as to request they create for you, is obscene. As far as I can tell, the quality is good and nothing is hidden about what you are receiving. If you can make something the same or better for less cost to yourself in time or money - great, do it!
And at the end of the day, look, pinball stuff is expensive. You aren't dealing with large market forces, you're dealing with niche collectors and hobby creators. Without the money behind it to fund these semi-esoteric after-market pinball devices, they probably wouldn't have been created and circulated to begin with. If you want art to be created and sold you have to buy art.