Unfortunately, the term Wireless Internet is adopted for two different systems.
1. You have an Internet connection at home (or you are going to Starbucks), and you want to connect your laptop to the Internet.
Such a connection will use WIFI devices, i.e. you buy a PCMCIA WIFI Wireless card, you install it on the Laptop, and you can connect to any local Access Point or Wireless Cable/DSL Router.
Current price of Wireless Card $60-$100.
2. There is no Internet connection around, and you want to connect.
You have to Wireless Internet Services from one of the Wireless Telephone providers, and they will give (or sell you) Telephones and cards to connect you computer to the Internet. (via wireless telephone line).
For real price you will have to contact your Local Wireless Telco.
The first option connected at max speed to the Internet, but you need an already exist Internet service.
The second way can be extremely expensive, and painfully slow. However, it is a good option for people that need to be able to access email, and office information from anywhere in the country.