I bought a 1:43 BTTF DeLorean by Vitesse (SunStar). $50 is kind of expensive, but I wanted to have one on my desk since the 90's, and this one comes in a nice display case. The metallic finish on it is just perfect. It competes only with the HotWheels Elite 1:43 version, but on that one the colors are completely wrong, the doors don't open, and even the shape of the rear wheel arch is wrong.
SunStar also makes 1:18 version, but it's much more expensive (on eBay), and the level of detail on that scale doesn't look as impressive as on 1:43.
They have various versions of the car from each movie (but not from the very beginning of the 1st one, for some reason):
https://www.sunstarmodelcars.com/product-category/vitesse-143/de-lorean/https://www.sunstarmodelcars.com/product-category/sun-star-118/movietv-car/ 