Today (11 December 2014) sees the General Availability of Microsoft Azure RemoteApp. This service delivers Windows applications from the Azure cloud and is licensed with a choice of two USLs – Basic for lightweight LOB applications (data entry, for example) or Standard for productivity applications (Office, for example). 40 hours are included in the starting price ($10 and $15) and any overage is billed hourly up to a capped price of 80 hours ($17 and $23) and after that there are no more charges.

See this Microsoft page for full details and some very useful FAQs: http://bit.ly/1slel6c.