There's nothing more galling than paying too much because you didn't know your options, like that time you shelled out $500 outside the Spectrum, only to find that WHAM! reunion wasn't sold out, and didn't even exist! At least know your parking options, with BestParking.com.
Just relaunched by a guy younger than your little brother, BP's a freshly beefed-up & redesigned free site that aggregates daily and monthly rates at 150 garages throughout Center and University City, so you'll never again default to having your car guarded by a guy who regularly sleeps beneath one. Choose an address, neighborhood, cross street, or "attraction", and enter your ETA/ETD to generate a Gmap that displays scads of nearby garage options; then click the rate calculator to estimate and color code actual cost at each spot (you could try to do it yourself, but if you're that big a math whiz, how come you spent $35,000 on a used Buick Reatta?). Scrolling over icons reveals further pertinent details: address, hours, indoor/outdoor, cash only, overnight options, and phone number, so you can confirm rates, make a reservation, and ensure the place isn't already at capacity when you arrive, drudging up painful memories of having to ride in the teacher's car on field trips.
BP also provides a mobile app that's compatible with even the most basic devices, as well as a brand new feature that provides rates from facilities throughout 65+ US airports, including 10 at PHL -- empowering you with a choice of where to park before you...Go-Go.