We only take in laptops and netbooks. No charge and we can give them the hard drive or destroy it. Some want it destroyed in front of them but I don't do that so I either offer to give it to them or not take the machine. If the drive is inside and we need to take it apart we charge $20 to remove the drive but they have to come back for it the next day.
We are getting more recent machines, especially "cooked" machines with bad SB or GPU issues but the rest of the machine is good. Sometimes I keep the guts as we can use them elsewhere. Ram, HD, LCD, WIFI, batteries all are saved and used in machines where the customer is willing to take a used part.