it depends on your needs what type iPhone's case you want to buy. Also you have to think about the price range you want to spend! In my opinion dont buy a case with 3$ but also avoid to buy and an expensive one! I have bought this aluminum case for 12$. I used it for over a year and my phone 4s is protected. Take a look here
This InfinityAppsTand iphone4s case and stand is not cheap, but if you get what you pay for then it's the one you might want to look at if someone else is paying for it. The case is magnetically couple to the stand so you can mount and dismount really fast.
it depends what your looking for.If you are looking for something slim personally i like Ozaki iPhone cases they are very slim and nice design.If your looking for something unique and very stylish i would recommend exofab.com they are slim gel cases that help you take the best selfie pics bc they cases sticks on glass surfaces and nowhere else, so you can stick it on any window and take pics ,facetime etc.
Last im always on the look for unique cases if anyone has any brand to suggest please do!