Interesting, I've seen those but it never occurred to me that they're collectibles. Shows you how much the hobby has changed since I've been out of touch.
Finding meteorites can be extremely difficult, but there are ways to make it somewhat easier. I would advise anyone to look at as many meteorites in their natural state as possible, in museums and such, and look at as many as you can find in high definition photos. Color is great, of course, for example if you can find a copy of Bob Haag's Field Guide of Meteorites, but black and white photos are even better because what you're looking for is surface features that don't quite match the surrounding rocks.
The best source material I've found is Nininger's 'A Photographic Study of Surface Features', Part 1 (Shapes) and Part 2 (Orientation). These two books are long out of print and good copies will always be expensive, but they're worth it. The goal is to train your eyes to pick out the subtle differences between ordinary rocks and meteorites, which will make it easier for the best optics ever made (your eyes) to spot them. My worst-case scenario is to see a real one and fail to identify it, leaving it to weather and fall apart because I was the only one to see it for...centuries?
After years of neglect I'm just now cataloguing mine and documenting them for insurance purposes (along with all the telescope equipment and my vintage soda bottle collection), they probably couldn't be replaced but at least with documentation of values I may be able to recover the investment.
The ANSMET (Antarctic Search for Meteorites Program) books are very good source material, don't know where you'd get them now, I got mine on a free offer many years ago. from the publisher (I believe). Meteorite! Magazine is a good series from the Arkansas Center for Space and Planetary Sciences, University of Arkansas at Fayetteville.
Looks like you have a good start on a great collection, keep adding to it and it will be a treasure you'll never get tired of. After all, how many people can truthfully say that they have material that didn't come from Earth?