I've never ordered any off the internet but to get more responses it might help to explain what type of tires you're looking for. Also, good in what way? Are you looking for a certain type of tire, or a dealer who has a good cross-section of tires, cheap prices, long history, etc....
If you're looking for regular ag tires I'd wonder if you've looked locally and if so what about those that are available local to you aren't you happy about?
Shipping can be pretty expensive depending on the size of the tire you're looking for. I will offer one bit of advice. If you don't need them right away watch auction sites (The big "E" for example). A few sellers like McGrew Equipment out of SE PA regulalry has slightly used sets that can be had for really good prices. I picked up a set of turfs for my Kubota that I had at the time for $103. I opted to pick them up while I was over there on bussiness but even with shipping I would have svaed a fortune. Wheels and tires from Kubota were over $2200 new so even if shipping would have been $100 I would have saved 90%.
Otherwise you'll need to provide a little more info I think to get others here to offer up some advice or even personal experience.
Good luck.