Consider checking to see if there is a local tropical fish club/aquarium club whatever in your area, if there is and you get in touch with them I am 100% sure someone would be more than happy to give you a cupful of gunk squeezed from their filter--which is exactly what you want to get your cycle jump-started in a jiffy.
It's also a great way to meet other people interested in the hobby (who can give you good, solid advice--unlike 95% of pet store employees who either don't have a clue, or else will say anything they think you want to hear just to make a sale), and get your hands on lots of rare fish that you'll likely never see in your local pet stores--or, get your hands on "common" fish but at a much reduced price. Many aquarium clubs have monthly meetings with fish auctions where you can get a whole bag of nice fish for almost nothing.