A laptop can be cheaper then a desktop computer for some people since it has a lot of parts built-in like monitor, webcam, speakers, microphone, memory card reader, CD/DVD Burner, wireless wi-fi, battery,touchpad, keyboard, HDMI port, and other accessories built-in to the laptop, and you can get a Windows 7 laptop for under 400 dollars these days.
Plus, Laptops generally uses less electricity then a desktop.
It is also easier to upgrade the RAM, and hard drive on a laptop since you do not have to open the entire computer to change RAM, Hard drive, and other cards like Wi-Fi card out of a laptop. You just need to unscrew a door to take out the RAM, hard drive, and Wi-Fi card if they break or needs upgrading.
But, if you are a gamer, poweruser, or a heavy multi-tasker, a high end gaming computer desktop would be cheaper then a gaming laptop.
The cheapest full sized laptop is probably this one from Walmart: http://www.walmart.com/ip/HP-15.6-320GB-2000-239WM/16662287#BVSecondaryCustomerRatings
Netbooks are probably the cheapest mini-laptops, but they are not very fast, and only good for e-mail, and maybe YouTube. http://www.walmart.com/browse/Computers/Laptop-Computers/_/N-96gxZ1yznsvg?_refineresult=true&catNavId=3951&ic=48_0&path=0%3A3944%3A3951&_mm=5up
I agree High Quality Gaming is best on a Desktop PC, but for almost everything else except for 3D and animation video editing a laptop would be good enough.
I mostly use my Laptop for Internet use as well since it has a Wifi wireless internet card, speakers, monitor, webcam and mic built-into it, so I can Skype video chat with relatives which I rarely see since they live in the US, and not Canada.
I also use my laptop on the second floor when relatives are living in the computer room in the basement for their 2 week vacation since I feel they might not appreciate random YouTube videos with Jpop, Kpop, Cpop, and foreign music tracks, or my geeky hobbies of watching anime, Computer videos, and Cosplay on YouTube. Plus, it allows me to use the internet longer since I won't be annoying anyone with my videos at night in the basement when I'm watching videos on the 2nd floor where no one is sleeping or relaxing, yet when there are guest in the basement.
