The Trezor wallet works with multiple currencies and works as a password manager, two-factor authentication device and other useful features. Also ranked 1 in What are the best sites to buy Ethereum. App Store Preview. So the app is pretty great when it comes to buying crypto, they can give you the funds immediately at the current price of the crypto, so high purchasing fees and selling it on a quick time line are virtually non existent when you are making small orders, most likely biggers as well. Size All it takes is a bank account or debit card.