In addition to what the others have said, buying at a shop, assuming you find a GOOD shop, is well worth the extra money. Often times you will get a free setup/tune included with the purchase, especially if you buy the accessories there. When I worked in a shop, I also made sure the person, especially if new to archery, left the shop knowing the basics of how to shoot, basically this was a free 30 minute or so shooting lesson. Often included discounts or free range time, discounts for xx week/months on future purchases, free 1 year tuneup.

Buying from the shop is a bit more upfront money, but well worth it in the long run, you will start a relationship to help you sort out bow/shooting problems, get advice etc.

If you go into a shop to test shoot bows, you are taking their time, then you leave and buy that same bow elsewhere? Expect to spend top dollar on any future things in that shop. They are making an investment in you by spending time with you, setting up the bow to shoot etc. This takes a considerable amount of time if you are shooting several bows, they will let you walk out without the bow, however if you buy it elsewhere, they will rightfully be upset. If you come back to them to get it, they will be happy.