Working your way through the mazeof rental car charges to the best deal isoften a mind-boggling exercise. There aresome general guidelines, however, thatcan help you lower the rental car tab.One of the Savvy Traveler's (www.savvytraveler.org) top tips is to avoid airportrentals. Add-on fees and taxes can add toyour airport rental costs; by taking a cabinto town, you can often get the samedeal for less. Similarly, suburban rentalcenters may have better prices thandowntown locations. Use Internet travelsites like Travelocity.com to search outthe best dealsâ€”and start early. Unlikehotels and airlines, rental car agenciesgenerally don't charge a penalty fee if youcancel an earlier reservation.