It won't EVER be cheap, and possible is many years in the future. It's not as simple as looking at it under a microscope. The discovery of a mutant allele requires an incredible amount of research and funding, and that's just the process for determining what causes a very specific trait.
Once that's done, you still have the cost of DNA analysis for each and every snake (and testing can cost thousands of dollars each). At this point in time, trial and error is about the only thing you can do without investing literally tens of thousands of dollars to determine if you have a het albino.