Fred:
I have background in radio/electronics, so I did buy a radio for my 57 truck off eBay for good price. I rebuilt the radio for about $75 in parts. I really didn't think it operated as well as it should, so when an opportunity arose to buy a rebuilt one from a professional at a very good price, I did. It ended up not being any better than the one I rebuilt. However, that radio was better than mine on the inside. Finally I just got tired of AM talk radio, I purchased a "Custom Sound" radio that looks like the original and bolts in without cutting. I provide that background for expressing my opinion.
If you don't have an electronics background, it would be hard for you to repair a non-working radio. Often it is more than just replace & repair. Also, while most of the parts are fairly easy to find, sometimes only a person that works on these type of radios on a regular basis can get access to certain parts. This is especially true in the case of transformers, rf coils, etc. My experience was lucky, I was able to find the parts I needed. Finding tubes is usually easy enough, I just replaced all the tubes on general principles. There are websites that special in in old radio parts, so that is very helpful. I did find that the professional rebuilder of my second radio didn't use the same quality parts I did, e.g., I used an electronic multi-vibrator ($30), he used an electro-mechanical one ($10). Basically, assuming you don't need parts that could only be acquired from a "donor" radio, this is very do-able if you a reasonable background in electronics and are willing to look for parts (on the internet and your local electronic parts stores - generally not RadioShack though). Otherwise, my opinion is that you should search for the best price (there are a number of people that advertise on the internet relative to to auto radio repair) and use their services.
