A friend of mine is gong to Miami next month and Im planning to give her some money to buy me an R7 card. I would like to know how can I check the prices in physical stores in the city, I have been using TigerDirect as reference, but I have heard that prices in physical shops tend to be higher than online prices.
What reason are you looking at R7 240/250?
Their performance is extremely low, only useful if you need to add extra displays for office work or such. If you intend to fully utilize them for gaming or other purposes you would get much more value for your money getting something different. Even the 260x would be around twice as fast.
These R series cards are mostly re-badges/tweaks of last generation, and you may find some of the "older" cards on sale. The 260x is basically a 7790, while a 7770 would also be an O.K. choice around $100. Much better than an R7 240/250 at $70-90.
Online you can get the "older" 7850/7870 cards around $100-150, they are also labeled as the R9 270/x cards now and are another significant jump in performance. In store they may be closer to $200 but it might be worth keeping any eye out in case the store is trying to clear out the "old" inventory for cheap.