What types of gift cards are available with the coin sorter

All types depending on the one u want(money)

I have no clue

You can cash in the voucher or some will wave the fee if you use the voucher to make a purchase in the store.

It's just like money once you turn in the voucher.

You can redeem The Coinstar vouchers at any cash register and purchase anything you want in the store with it.

Check with that particular Walmart to be sure

I'm not sure about that area. I know they have a large selection by the check out lines, on the grocery side. Good luck.