This is interesting to say the least. To be honest if it is a really costly pet, higher than $100 then odds are you're not going to find someone who would be willing to negotiate via services. I mean, most will negotiate price but I've never seen high end UC's go for services.
You never know though! Someone might need like 50 petpage applications!
I wish you the best of luck and will be stalking this to even see if people would legitimately do this.