Yes, a one-time registration fee is fair, to cover data management.
One thing to keep in mind for anyone who is thinking of chipping an animal – I don’t know what the current state of regulations/standards (or lack thereof) are for domestic critters, but PIT (Passive Integrated Transponder, that’s what a chip is) tags come in different frequencies. For example, with the tags that are most commonly used for wildlife, older tags from 10-12 yrs ago used a different frequency (125 kHz) than newer ones (134.2 kHz), so you have to make sure your readers are backwards-compatible if you have older tags out in the field.
What that means is that owners should look into whether there are different frequencies out there in domestic animals & should try to use what is most common. Especially if you are installing a chip for ID in the case of loss or theft, you want to give them the highest probability of being detected by the most readers. Readers CAN detect multiple frequencies, but not all of them do, it varies by model.
My discount insertion offer stands, heh.