My son just bought himself a laptop computer, and of course wanted to be linked up to the internet. The problem was there isn't a phone line in his room to get access via dial-up, nor a cable line in an accessible place to hop on board that way, which is how we get our internet access for the household desktop computer.
After getting an estimate to have the cable company come out and run a new line to his room and computer area, we decided to go to Staples and buy the Belkin Wireless G Plus Router for only $34.99.
That's the obviously cheapest way to go, and having a wireless network established within the household allows him to access the internet from any place he wants, and not be locked in one set position, because it has a range of 100 feet. It also allows the possibilities for my other two kids to eventually get their own laptop and get in the wireless network without any cost at all!
It was extremely easy to hook up and get running. I would recommend it to anyone who has 2 or more computers in their house.