Rent a car, for a buck/euro a day

For 1 euro (roughly USD 1.1) a day, you can rent a Smart car from Maxhopp in Berlin and Hamburg. Sound too good to be true? (Or, from an entrepreneur's point of view, too painful?)
It helps to understand that Maxhopp is not really a car-rental company: its main business is advertsing. Maxhopp's rental cars are literally plastered with ads (source: tjacobi.com). In fact, this rental company must be the only one in the world that encourages you to rack up as many miles as possible, without extra charges.

Requirements? Customers rent a Smart car for exactly three days, and have to do at least 30 kilometers (about 20 miles) a day. The cars also don't go much faster than 60 kilometers an hour, which is no problem as long as you drive within Berlin and Hamburg city borders. So far, Maxhopp is doing well: a Munich branch is in the works.

Opportunities

If you throw in a couple of environmentally friendly cars, and perhaps even some bikes, this concept should do well across the world. After the growing popularity of car sharing ventures and low-cost car rental companies, will we soon see ventures actually paying consumers to happily roam the streets?