I would do a search on google for the company name and model number for sale, and see if there are links to people selling the model you are and you could see what they are asking for it and what condition it is in, or if that includes extras, so you know if their price includes extras you need to deduct from their price to come up with yours. Otherwise you should factor how much you paid for it, how old it is, and what condition it is in. It won't be much if it's only Dolby prologic since most can buy a dolby digital home theater system for under $100. If you want further help, I suggest posting on here the model number, the price you paid for it and the condition. That way people can give you an accurate estimate on what you should try to sell it for. Hope that helps you.