This is comcast cable company. Typically cable companies offer services such as phone, Internet and tv and they have package deals that they typically give you a cost break for a year.
Broadband is a high speed internet connection.
Basically the differences in speed results in the difference in cost.
Cable companies typically have the fastest speeds. DSL are typically phone companies like AT&T which offer higer speed but not quite up as fast as Cable.
Satelite is typically used in areas where cable and/or DSL don't exit. They typically get the receive the internet through the satelite and use the phone line which is slower to outgoing transmission.
Both DSL and Cable will require a technician that will connect the home and set up a modem that devices can be connected to to access the internet.
A modem is the device that connects to the internet. The technician will connect the wire he brings from outside the house to the modem.
Wireless - To broadcast the wireless signal you need a device called a router. Some DSL services the technician installs the modem and it acts as a router and a modem. Meaning that it broadcasts a wireless signal without the need of purchasing a router.
A must is security where you can prevent neighbors from accessing your wireless network. Typically the DSL modem also have the security built in and they have a tag on the modem with a password to the wireless network.
I myself have a cable internet connection called roadrunner. It has a modem and I connect a router via a network cable to broadcast wirelessly. My router is made is a linksys which is now owned by network giant Cisco. I had to setup the password myself to protect against neighbors getting on my wireless network.
Based on what is needed by your friend web browsing and email speed isn't much of a factor for but if you want to watch video that are streaming on the internet speed is a factor. Now if those videos aren't on the internet they could go with just the basic internet.
Remember Mc Donalds and Panera bread and many other businesses now offer free wireless internet.