Well, it depends...If you buy from a computer store or somewhere like Best Buy. They will run about 80 -100 dollars. However, you can go to
www.pricewatch.com, and get one for almost as low as 20 dollars. But its not that easy in just going out and buying one. Three things to remember....1. You must buy a processor that is compatible with your motherboard. If you have an Intel Pentium based processor in your system now...an AMD will not run...you must purchase another pentium. (AMD Processors are less expensive and perform better in gaming than Intel Pentiums, even if the speed is rated slower ;) ). 2. If you buy a processor, dont forget to buy a heatsink with it too, or else that processor will be gum within a few minutes. 3. If you don't know how to install a processor..PLEASE take it to someone who does. They are easy to install, but easy to mess up. The best thing to do is to take your system to a computer store or friend you trust, and let them pick out a processor for you. Just a little bit of extra info :)