I don't know anything about tattooing snakes (and honestly, anesthesia for your entire collection sounds like it will get pricey...), but if you want to save money on chipping, try calling around and finding out what vets in your area will charge if you bring in the micro chips yourself. You can order the microchip kits off ebay (comes with the syringe and everything) and some vets will put it in for free or for a small fee.