There are several sellers on eBay that know how to spot products that are undervalued, purchase those products, then resell them later at a higher price either back on eBay or on another site that allows sellers to sell, such as Amazon.com or possibly even Craigslist or Google Base. The key to success with this method is to have spent enough time on eBay or done enough research with a tool like Terapeak that you'll be able to tell which products represent a "good deal" vs. a "bad deal".

Here's an example of one of the types of products that you can do this with and how you can do it. Take something that will be relatively popular such as an iPod, cell phone (pick a popular model), or handheld gaming device. I usually pick things that are easy to ship so that when I get them in, I'll be able to ship them back out with USPS Priority which also gives me free shipping materials.

In the case of handheld gaming devices, such as the Sony PSP, you often find that people selling their PSP are also selling several games or UMD movies that have come along with the base PSP. Once you know the approximate sales price of the Sony PSP on eBay or Amazon, you'll be able to target searches on eBay for Sony PSPs for sale and make your buying decision based on that going rate. Always purchase from someone with established feedback and review carefully the product description so you know what you're getting.

The search I do on eBay for the handheld gaming devices is the name of the unit (in this case Sony PSP) along with the keyword "bundle" then add as many other qualifiers as you want to get to where you have the exact search you're looking for. You can also put in qualifiers such as a price between two numbers and also the option for "buy it now" which will typically give you some of the best deals out there.

People post things for sale all the time with a "buy it now" option simply because they want to sell something fast. They'll put down what they believe is an acceptable price for them and it is often much lower than the true value as determined by the eBay marketplace.

Once you find that you are the owner of this new Sony PSP core unit along with a handful of games or UMD movies, you can then part these items out and resell them separately or take some of the more valuable games and resell them separately leaving a "bundled" item still in tact. These items can be resold on eBay, Amazon or another venue such as Craigslist.

Again, the key to success with this process is really knowing the average selling costs and also becoming a better observer of items that represent a good deal or not. If you stay too broad or spread out in your research, you may not achieve the level of expertise with one item that will allow you to make money consistently on eBay. Focus on the popular products and you'll do just fine with this strategy.