A cheap computer desk would be a desk to hold a computer on which would be of very little value or sold for very little. Anything under $50 would be considered cheap.
You can find computer workstations desk for cheap at Bizrate. They provide high quality desk for cheap, for your office.
It is likely that you can find a computer desk for lower prices on sites like Amazon and Overstock. Here is a website with many options for cheap computer desks. http://www.cheap-computers-guide.com/cheap-computer-desks.html
If you need to find computer desks cheap, consider searching at second hand stores and garage sales for the best deals. It also makes sense to re-purpose a small table or writing desk in some situations.
Computer desks vary in size and shape depending on the use needed and their materials. A large variety can be found at the following web sites: Walmart.com, OfficeDepot.com, and Staples.com
One option would be to explore your local area to see if there are any businesses going out of business where you could purchase their used computer desks at an affordable price. Otherwise, check out www.computerdesks.com
Argos is very popular for buying cheap desks. The starting price for a desk at Argos is £13. Ikea also offers a range of cheap desks or laptop tables.
At any sensible furniture store, although you can often find them cheaper online.
Department stores like Sears, Target, Walmart, or KMart often have cheap bedroom desks for sale. Other than that, Ashley's furniture and Bob's discount furniture also sell cheap desks.
You can purchase cheap computer desks from Office Depot, as well as Staples, and Sam's Club. These retailer's sell products like what you mentioned for under $100. Keep in mind, you get what you pay for, so do some research before making a choice.
You can find some cheap corner desks at local department stores or even buy them second hand from others.
There are many stores where one can purchase a cheap computer desk. Online one can check Office Depot, Walmart, Target, Best Buy and Amazon. If you prefer a physical store try Walmart and Target.
Cheap computer desks can be purchased at discount office furniture stores as well as some furniture outlets. It really depends on what type of desk you are looking for, and the amount of space that you have for the desk. I found several sites with discount prices, but the one that had a great selection as well as deeply discounted prices is found at this link: http://www.furniturewholesalers.com/search.aspx?q=computer%20desks