I would pay $50 for a license plate but I think $70 is a bit much. $125 for a lightning hook that isnt very screen accurate is a no go with me. If it actually looked like the one in the film, then maybe (it was basically a fishing rod) but its still a bit steep. I dont wanna sound like im bashing someone elses work though (which im not) as they are still nice pieces and its down to the individual as to what they want and how much they are willing to spend. Skill also comes into it as you say and to make the one thats $125 looks fairly easy (alot more so than the one im attempting) to accomplish (some small cable ties, wire hook and a 2.5mm-3mm dowel with a length of roughly 60cm as the main rod, not sure what he has used for the cable though, looks like painted parcel thread maybe).
Regarding these mats, its a fairly simple thing to create. Now, I could never make one of those metal license plates so I can see why they cost what they cost but Im not willing to spend money on something I know I can do myself. Fans mats do look pretty good and more professional than what I have created but I am more happy with mine as its something I created and at a fraction of the cost. I still have my template which I may tweek further and I may find an even better material.
If anyone can suggest a way for me to upload the template so that all you have to do is print it off on A4 paper so that its the correct size, im more than happy to do that. That way, you can source your own material and make it yourself for next to nothing. Also, by going this route, everyones delorean will be slightly different and unique.
I think im one of the few people who really doesnt care about foot pedals. I would kinda like the handbrake but I kinda doubt there would be much room for it as its supposed to sit between the seat and the door. A small piece of rounded plastic would do the trick, maybe even that piece on a pen lid could work. Seatbelts are another thing I dont care for (marty and doc never wore them) but probably is a fairly easy thing to make, (im still considering painting the catches black though). However, I dont think there is room to add them where they should be. Ive not really checked to see. This is the only pic I have that gives you an idea on where the belt sits.
View attachment 284217
Handbrake position
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The annoying thing, the more I look at interior pics, the more I want to repaint the whole interior to be the correct colour grey. But that would require dismantling the thing which I have no confidence in doing at all. Delorean interiors came in 2 colours only, grey and black (there was a concept of red/burgandy which never saw production and any other colours you have seen are customs owners have done themselves). The BTTF interior was grey like the 2 pics I just posted. Its mainly the dash that annoys me where the steering wheel is attached. Its just screams cheap plastic to me.
Each to their own, I suppose.
but see why custom work can be so relatively expensive? If you look closer you will find that it actually is not expensive. Making custom things is time intensive. Even if it is only about these floor mats. It is about getting the proper shape, sourcing a proper material, making trial and error with possible waste of time and money. That has to be compensated by the amount you collect from a relatively small number, not knowing how many will be interested in the end. Then you need to make pictures, fabiracte them all, handle shipments, handle lost or damaged shipments and so on. Not saying it can't be fun but it surely is not as rewarding (financialy) as some may think and always consider that it usually is free time people invest.
Totally get what you're saying about finding ways, that is the more rewarding part of the work, well at least if it works. 
