Along with the different network cards on the market also come different prices. Most of the time the best card sells for the highest price.
Many companies make network cards.
I'm sure you're familiar with 3Com and IBM, but there are so many other little companies out there. Until recently, I was always afraid to buy a no-name or smaller name brand card if I needed to use the device on a regular basis. Thanks to the durability and reliability of the network cards that I've been testing, I now have a renewed faith in smaller companies and the quality of their products. The company in particular that changed my mind is Linksys, which makes a variety of networking devices for homes and big and small corporations. I figured that I could get some generic card and it would work fine.