If your system is functioning fine and you don't have the money for a new system then I would say just stick with what you have.
I used to have a really old, sucky computer and I would have lag problems and my CPU was always running at high usage percentages. One cheap upgrade I did was to just add some RAM. I probably upgraded my computer for well under $100. That solved my problem for a year or so. As websites became more sophisticated, they started really bogging my computer down. I was having problems just surfing the internet. I decided to just get a new computer.
If you sit and watch the Dell Outlet, you can scoop up some really good deals. It takes a little bit of stalking. New inventory comes in constantly and you can get some fantastic deals if you keep your eyes open. The good ones always go quickly. Also, they tend to give out a lot of 15% off coupons.
A couple of years ago I bought a a nice desktop and a nice laptop from them. I think the desktop was $330 and the laptop was about $450. At the time they were very modern computers with good specs. Of course, any tech you buy will be outdated in 6 months, but they still work great now.
