Re: How much is it worth?
1. It might be the battery, and not the charging interface, check that out.
2. Check on the warrantee.
3. If its not the battery, find a competent computer replace place, and bring it in to them. Fixing this problem is cheap and easy (shouldn't cost more than $50 if it is the charing port). And it will increase the value of your laptop by atleast $100. Once you try to sell a product that has a defect like that, its value drops drastically.
4. TO determine how much it is worth, can you please post more information such ass the processor type/speed, memory type/amount, hard-drive size, internal WNIC? etc...