Welcome to the forum Steve. I'm glad you like the website and forum. It can be hard get a handle on how Reattas are priced. There are basically two groups of Reatta owners. Drivers and collectors. Reatta automobiles are the same way. You can divide them into at least three groups. Drivers like most of us have, collector cars that are rarely driven with low mileage, and parts cars. The differences in price between groups can be wide as you have found. You need to decide if you want a Reatta that you can drive and enjoy, or if you want a really nice, low mileage one that will be used primarily for car shows. Do some research on how the Reatta you want should be priced. In my opinion the best way to do that is if you have an eBay account is to go look at completed listings of Reattas that have sold. Pay no attention to the prices the sellers are asking. The amount they SOLD for is what counts. Once you have a good idea of what the Reatta you want should sell for, buy the best one you can afford. If you get a nice driver that has been well maintained you may not need a parts car. I don't have a parts car and I have made it 13 years without one. But I do have several frequently need parts on hand that I have collected over the years in case I might need them.
Parts for the Reatta are available. Just be careful who you buy them from (some sellers will take advantage of new Reatta owners) and know what the part you need is worth so you don't overpay. And lastly, being handy with tools and can do some of the work is a big plus if you are a Reatta owner. It can be hard to find mechanics that are knowledgeable and willing to work on a Reatta. Good luck with your search!