Copay Bitcoin Wallet (whose software is free) is an open source cryptocurrency wallet operated by BitPay, a popular Bitcoin gateway. While its internal structure can be a bit daunting for newbies, it offers a simple interface with good support for advanced features, and it does this not only for mobile devices but also for desktop operating systems (OS). However, its particular focus on the Bitcoin currency means you won't be able to use it to store the rapidly expanding kinds of altcoins. Similar to BRD, Copay Bitcoin Wallet is free to download and use, although you still have to pay recurring transactions charged by the Bitcoin network when sending currency.