AMD Sempron LE-1250
Well, folks, you can't get much simpler than this. AMD's Sempron series is the company's more affordable line of products, aimed directly at computer users who want something that is extremely low in cost and/or can be used in small computers with tiny power supplies. The Sempron name has been around since 2004, but it is a brand name rather than an architecture name, which means that the latest Semprons feature most of what you expect from a modern processor, but in small doses. It has two levels of cache, an 800Mhz Hypertransport link, and is manufactured on a 65nm process. What this means is that the LE-1250 is not an older processor, but rather a new processor made to very modest specifications. The LE-1250 is only a single-core processor, and it runs at a modest 2.2Ghz. I said small doses, remember?
Clearly, the Sempron LE-1250 is not going to be useful for doing anything related to multi-media tasks. High-definition content is out of the question, games would run poorly, and you might even find some of the fatter flash applications giving you trouble. But that said, it is worth noting that the Sempron LE-1250 is going to provide a great deal more performance than what you'll ever get out of an Atom processor, and there are millions of people with Atom-powered netbooks who don't seem unhappy with their systems. In other words, as long as your expectations are realistic, this processor will do its job. If you're looking to create your own low-budget computer, then you'd be hard pressed to find a better choice.
Speaking of budget, the Sempron LE-1250 is incredibly inexpensive. At 29.99, it is the cheapest processor that has been available in some time. Pair with a low-price motherboard and two gigabytes of DDR2 RAM and you'll be well on your way to building a full system for under $250 dollars.