In general, I would expect to pay $20 for a 128GB card, $30 for a 256GB card, and $60 for a 512GB.
The prices fluctuate all the time, so keep an eye out for deals. In general, I prefer the cards listed below, in order or preference. I recommend using a card from reputable brands like SanDisk or Samsung to use in your device. Some Android devices will have a microSD card slot, which is handy for storing game files.
Sandisk (left) and Samsung (right) microSD cards
