Depending on what shape your dryer is in, and the features that it has on it; a 2002 should have cost about $1,200 new and it would depreciate about  35% or more after about six years.  You should be able to get about $650 or maybe more, if it has all the bells and whistles and is still working just fine.  You might want to make sure to clean the lint from not only the filter, but in whatever way is recommended.  A large amount of lint is unsightly and unsafe.  You could take a great picture of it, and post on craigslist in your area, or kijiji.com in the want ads section.  If you offer to deliver it to the buyer, you could get a bit more money.  If you want to be firm on your price, check out the current value and depreciation rate in Consumers Guide online.  This way, when a potential buyer asks for the details and how you came up with that price, you will be ready to answer honestly.  Be sure to include the Drier's manual so that the customer will be satisfied.