"Turn your spare room into spare change" is the unofficial motto of new London startup Flexiroom. The start-up has launched an Airbnb-style website that could prove infinitely useful for those visiting during the upcoming summer Olympics in London.

The website provides an online platform for hosts and bed and breakfast operators to sell spare or open rooms for paying guests from all over the world, and offers an incentive for hosts as well. Up to £4,250 of tax-free gross income is allowed each year for people who rent out a spare room or rooms, thanks to an official government plan. This breaks down to £300 tax-free each month.

In addition to its UK focus, Flexiroom offers professional cleaning at no cost to the guest or property for anyone staying over a week.

The properties on the website appear to be affordable, although there aren't nearly the number of reviews we've seen on other sites. This is one site we'll keep an eye on for future visits.