See if you can find them cheaper than that... $42 each would be able to get games with there original boxes off of eBay for most systems, unless the game is rare. I've not used them myself, but there a fair number of collectors that use them on Youtube, looking them up on there would probably be a good idea.
If you're willing to do a bit of DIY, rental VHS cases --probably cents per unit used, and a dollar or two new-- can be adapted for all except NES. For NES, and non-DIY of the other consoles, I think you should be able to find rental or original cases for them on ebay for far less than $42 each.
Your math is wrong; the website says that the cases are only ordered by boxes of 100, which coms to 42 cents