I toyed with an idea a bit like that a few years back. The tokens would be denominated in your national currency (so no exchange rate volatility), could be bought or sold (in batches) for free (depending on mechanism), and were for online purchases or transfers only (so no interfacing with physical point of sale presences required). The purchases could be made for free via a bank transfer to a specified account with your account number in the reference field (these are normally free and near instant in the UK via the Faster Payments Service) and if you wanted to cash out your tokens could could similarly arrange a bank transfer back. It was to be completely centralised, so nothing like Bitcoin. It was actually meant for another idea which required an escrow service. There were no specific advantages to the "senders" of the tokens other than that they could use the other service, but the big benefit to the "receivers" of the tokens was that they didn't have to pay the high credit card processing fees or PayPal fees. Anyway, lots of challenges to setting up a service such as this, such as needing a business account to send/receive the transfers (business accounts in the UK attract usage fees unlike normal personal accounts), and of course all the payments regulation, which would have meant it would have been difficult to operate for free (although the idea had been that the other service would subsidise it).