Micro SD - What to Look For or Avoid??

[Puddin422]

I've never purchased one before, just used whatever came with the phone. I think this one did not come with one and I used the one from my Epic.

Is there anything I need to watch for when shopping for them? I've filled up both my internal memory and 16g micro SD.

Any really good deals anyone knows of? I'd prefer to buy from Amazon bc I have gift cards.