snake mites only come from other snakes that are infested. However when it comes time to lay their eggs they will drop off the host and wander away and find some really tight crack to wedge themselves into to lay their eggs. So yes, you can bring mite eggs home with you on supplys that you've bought at a pet store that may have snakes that are infested with mites.
When the eggs hatch they're like little blood hounds and can smell snakes from quite a distance away and will make a direct bee line for them
I help out a lot with reptile rescue with my local herp society. (I've been a long time member of the adoption committee) and remember one time a boa coming in that was the most infested animal I've ever seen. There was a roll of paper towels sitting outside of the cage it was being treated in, and within a very few days the end of the paper towel roll had many brown concentric circles going completely or mostly around the end of it. Upon closer examination those brown circles were completely made up of snake mites that had wedged themselves in between the plys of paper on that roll of paper towels. There were SO many of them wedged in there that they made several complete circles on the edge, it was just creepy. I wish I'd thought to take a picture of it.