I think micro chipping snakes is actually becoming more common...still not the norm by any means, but I know of a few people who do it, and more that are considering it. As far as costs go, I'm pretty sure it's not all that expensive, and if I remember correctly, if you are doing them in quantity, you can buy the syringes/chips and do it at home. For 2 pet snakes I wouldn't bother, but if you're buying/selling/breeding a decent number of animals, may be worth it.