It can be pretty easy to install more RAM, depending on your model of MacBook, and you didn’t say which model you had. Sometimes you can install more RAM from inside the battery area, and sometimes you need to take the back off the MacBook. But there are videos available that make it easy and all you’ll need are some small philips head screwdrivers.
More RAM will generally make your MacBook a bit faster, and the real difference will be when you use programs like Photoshop and video applications that needs lots of RAM. In my experience, more RAM will also make a MacBook run cooler, too, and the fan will run slower. Don’t expect that you will feel like you have a brand new MacBook, though. More RAM will make your MacBook faster, but it won’t be eye-opening faster. But if you use your MacBook all day long, I think you’ll see a difference in speed and temperature.
If you can afford it, go ahead and install the maximum amount of RAM, as that is the best value. Going from one GB to two will make a difference, but moving up from one GB to four or more will make the most difference. Installing more RAM in all of the MacBooks I have ever owned was worth it.
Take a look at Apple’s Knowledge Base article MacBook: How to remove or install memory, depending on your model of MacBook. And check these videos, too: MacBook, MacBook Pro Memory Installation Videos. (Select your model of MacBook and then scroll to the bottom of the page). Other World Computing is also a good place to buy RAM, too.
If you don’t want to buy and install the RAM yourself, call one of the local Apple authorized dealers in town. They may have a good deal on installing more RAM for you.