Pedicabs (ren2 li4 che1) are three-wheeled part-covered bicycles that are a good choice for sightseeing, especially through the hutongs, (traditional laneways) on your own.
They are available everywhere and are good value.
Be warned: you should bargain with the driver first, asking how much it will cost, giving clear directions etc. A legally registered pedicab has a certificate, and the driver should have a card hanging around his neck.
should be treated with caution. Although they are good for short trips (they will travel a good couple of kilometres for ￥5), drivers can be hard to barter down and may demand more money when you get out. Make sure you both agree on the fare, and the currency you're negotiating in, before you set off. Around tourist sites the rickshaw drivers have reinvented themselves as tourist attractions, now that their day-to-day role has been usurped by taxis. Be prepared for frilly seat covers and silly prices.