The starter version is a stripped-down Windows that uses as little computing power as possible with the most fundamental system processes and applications. It's being used in netbooks with Intel Ion processors so you have a lower power consumption rate. It's convenient for those who don't want to do much with their computer but want to be able to have a long battery life.
Personally I never liked the Windows Starter version. However, I do have an upgrade key to upgrade from Starter to the full version of Windows 7 Home Premium. A friend accidentally bought it and then gave it to me in hopes that I would someday find someone who might need it. The outside of the cover of this upgrade key box lists features of Windows 7 that apply to Starter and compares it to Home Premium:
Starter:
+ Makes the things you do every day easier with improved desktop navigation.
+ Faster and easier to launch programs and find documents you use most often.
+ Make your web experience faster, easier, and safer than ever with Internet Explorer 8.
Home Premium (includes those features of Starter, plus...)
+ Personalize your desktop with custom backgrounds, colors, and sounds
+ Easy to create a home network and connect your PCs to a printer with HomeGroup
+ Watch many of your favorite TV shows for free (FOOTNOTE: fees may apply, subject to availability) when and where you want with Internet TV
+ Watch your favorite DVD movies
+ Access your photos, movies, and videos from a PC running Windows 7 anywhere in the world
It looks like if you're solely using the Internet, you would be able to get by with just using Windows Starter.
But his mistake of accidentally purchasing that Home Premium upgrade might be your opportunity if you're interested in upgrading to Home Premium. I don't know if we are allowed to make offers outside of the "Selling" forum. Sorry in advance if this violate the Forum rules.