Used laptops are for more abundant now than they were even a couple of years ago. Sales have surged. The main reason for this is because laptops are cheaper than ever before and loaded with features. I read just the other day that laptop computer sales have exceeded desktop computer sales.
What happens a lot of the time is people trade in their perfectly good laptop for the latest and greatest. That's good news for anybody that needs a cheap used laptop. For the average user who checks email, surfs the net, and uses Microsoft Office a used laptop is perfect for their needs.
One method I have used in the past to obtain a used laptop is to keep a sharp lookout for the brand and model I want on Ebay. A lot of people will not buy used laptops because they afraid they will get a lemon. A way to reduce the chances of that on Ebay is to check the seller's feedback. If a seller on Ebay has the one that meets your needs make sure their feedback is in the 98%+ range or above. Don't be afraid to ask the seller questions either.
You can get a pretty good idea of what type a person you are dealing with by asking questions that you need to know the answer to. Just click on the Ask the Seller a Question at the upper right hand corner of the auction page. If the seller is prompt and courteous with an answer that's a good indicator. Sellers who are rude and late with answers to your questions are best avoided. Ask the seller why they are selling the laptop and if they have had any problems with it. Make sure you are getting the operating system software and the specific drivers for it. The drivers are not a big deal because you can usually download them off of the manufacturer's site. If you own a copy of Windows XP, it should work on newer used machines. Check specifications at the manufacturer's website to be certain.
So, you have found a used laptop and the seller checks out on feedback and email. The next step is to decide how much money you can spend. Set a dollar limit and stick to it. Only buy if it is a bargain. The fact is that most sellers on Ebay do not offer a warranty on what they sell. There are exceptions, and if you can find a seller with a warranty on what you want so much the better.