So up selling is a great way to increase profits.
Went to set up a new computer for a customer, they purchased it from a major supplier. They were up sold Office 2010 product activation key and new copy of Norton.
Now I am happy to up sell, but 2 points here. The customer already had an active subscription for the Anti-Virus so this was not needed.
The Office was even better, the computer they purchased had Office 2007 pre-installed, and the customer had a license for this. Even if they wanted to have Office 2010, the product key wouldn't have worked.
Just go careful what you purchase through an up sell, make sure you need it.