BestParking.com is a handy mobile webapp for finding the lowest prices on parking nearby. It lets you search for the cheapest and and nearest parking garages and lots in 30 cities and at 79 airports.. According to the publisher the app saves users an average of $16 everytime they park.
You can either choose an airport from a list or select a city and either enter an address or pick a neighborhood. You tell BestParking your arrival time and how long you intend to park and it returns a list of open spots and prices at nearby parking lots and garages. Results are displayed on a map and sorted by distance with the best prices highlighted. You can also sort results by price. Clicking a result in the list brings up a page with hours, click to call number and a detailed map.