Pedigree Query

Would it insult my vet to ask him to write a prescription so I can order online rather than buy from him?
Internet and magazine prices are WAY BETTER than his, and I do not want to make him mad!!!
Where do most of you buy medications? Is there any company who is the best in your opinion?

I did this and my vet asked what am I paying...then he matched it!
Shows some vets are really good, bu tI have heard horror stories of ones who tell you to find another over a simple buy it yourself script.