New mobile providers seem to be springing up left, right and centre these days. Already this year, we've seen BT and Carphone Warehouse join the MVNO club, not to mention Sky's after its own membership and FreedomPop's due to unleash its completely free mobile plans on the UK sometime this summer. And today, we welcome another new kid on the block going by the name ROK Mobile. Launched last year in the US and going live in the UK today, ROK Mobile is aimed specifically at music lovers. The new MVNO, which piggybacks on Three's network, offers just one SIM-only tariff on a rolling one-month contract. For £25 per month, you get unlimited calls and texts, 4GB of 4G data, and -- here's the hook -- free access to 7digital's music streaming catalogue through the ROK Mobile Android/iOS app. Available only to paying customers, the app lets you stream over 20 million tracks, build playlists and download music for offline consumption.