A home computer desk needs to work with you - not against you
Make sure the home computer desk will fit where you want it to go
Go ahead and measure the area where you want the home computer desk to go, also account for the chair that you will use. Keep in mind that generally, depending on your equipment, you can't push the home computer desk all the way back against the wall since the cables usually run off the back, this isn't an issue if there's cable holes in the desktop.
Use a template of the home computer desk to determine if it'll be large enough
Once you know the maximum size of home computer desk you can get I suggest laying some cardboard out on the floor as a template. Once the cardboard is layed out, representing the home computer desk, go ahead and position your equipment on it. Make sure that there is ample room for your monitor, speakers, mouse and everything else that'll need to go on the home computer desk.
I know this may seem a little stupid, but not having enough room on your desktop for even a coffee mug is horrible annoying. You can avoid this by this simple exercise. Also, for you gamers out there some of the newer gaming keyboards are quite large and as you know you'll need room to maneuver your mouse around as well.
Keep in mind that if the home computer desk does NOT have a keyboard drawer than it'll have to go on the desk top also.
If the home computer desk you are considering has an area to put your computer make sure it's large enough to house your PC comfortably, you should also have enough room to allow proper air flow and access to the drives and buttons.
Note: If you have a high end gaming PC with multiple video cards than air flow is a real issue. Make sure the computer isn't in a 'box' with just an opening in the front.
Some other things to consider when purchasing a home computer desk
Look at the available drawers, shelves and other storage areas. Make sure they'll be large enough for your equipment. There's nothing worse than getting a new home computer desk built and then discovering that the area to put your monitor is too small.
As far as material a home computer desk can be made of wood, glass, metal and even plastic, this is a personal choice, but I always go for wood personally since I just don't trust glass and metal can be quite heavy and if it's cheap metal it can bend.
If you're specifically looking for a small corner computer desk here's a great article that will help you find the best one.
How much does a home computer desk cost?
Well, that'll depend on the material, quality, size and other features, not too mention if it's on sale or not. A Bush computer desk is generally a great value for the money. I'd suggest reading computer desk reviews on sites like consumer reports and consumer search, they have unbiased computer desk reviews written by users just like yourself and often times have the lowest prices listed right there in the computer desk reviews. You will, of course, find many useful links on this page too.