[Asif Adnan Ahmed]

Ultra
Extream
Extream pro

Need to know are every class is compatible. Also need the brand rating. From where i can buy a good one.

[IAmSixNine]

They will all work just fine for normal android operations.
Amazon, best buy are tusted sites to buy from.

[ironkhalid]

I use Samsung 64gb class 10 evo
Good price, as cheap as $30
Quick data transfer, no complaints, very happy with it
Slickdeals sometimes will have deals on them,
Stay away from used SD cards and questionable dealers/non name cards

[TarekElsakka]

I got a cheap class-10 Kingston Micro SD because that's all I could find in the nearby electronics store and it works brilliantly and is quite fast.

[Mooncatt]

The main thing is to stick with the name brands from reputable dealers. As for which version is which, look at the class rating. The higher the class, the faster the card, which can make a difference when recording HD video directly to the card.

[BlueAlchemy17]

I would go with Newegg for any electronic component purchases over Amazon every time. Read the reviews on Newegg about the different micro SD cards. I was going to go with a Kingston but it didn't have good reviews, have a Patriot and love it. You're generally safe with any brand that is known for memory (SanDisk, Patriot, Kingston, Corsair, etc.)