I recently received a tennis bracelet too. I think it's pretty important to know the specs (color, clarity, size of each stone, metal) in order to consider whether you're getting a good deal. Whiteflash and Bluenile prices were the benchmarks I set for myself (i.e. is the jeweller charging similar or a little above these online prices). I started off looking at ready-made ones in jewellery stores, but these were too expensive for my budget and there was always something "not right" (e.g. too big, too small, the bracelet was too rigid, or the bracelet "flipped over" when hanging over my arm). Eventually I started considering getting one custom-made as the prices I was quoted for custom-made were much cheaper. I ended up getting the exact thing I wanted, and the process was very fast and easy. If you're interested, they ordered the bracelet, the stones and I went in once to look at the bracelet, adjust the length, and look at the loose stones. Then I just went in one more time to pick it up a week later.
Anyway, in my experience, jeweller prices are always going to be higher than online prices. But I didn't go with online in the end because the extra money paid went into supporting a local business, free lifetime cleaning, polishing and checking the setting, and a warranty (i'd hate for the settings to come loose or the bracelet to break if I bought online).