I know it's hard to see in that picture, but 1ct diamond bracelets have teeny diamonds - there's usually approx. 32 diamonds or so in a typical 7" diamond tennis bracelet, so that means they are around 3 pts. each. You may want to go to a store to look at some so you can see what I mean. The diamond quality is important too. If you get a bunch of cloudy yellow specks of diamonds, it's just plain not attractive.
Considering you are working toward a budget of $500, I would try to find something of a higher carat weight on ebay. The only thing is don't try to buy November - December because the prices go up because everybody and their brother's trying to buy one for xmas presents. Best time to shop for them is in January - even February's not a great time either because of vday. Actually the summer and fall are ideal for buying diamond tennis bracelets. I've bought 2 from ebay, this is how I know. I bought one 5ct. one for $900 SI H-J, lost it a couple of years later then bought another one with a safety chain (4ct SI J) for $800. You'll get a lot more for your money on ebay.
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"Fashion can be bought. Style one must possess." ~ Edna Woolman Chase