Online shopping needs to not be limited. I purchase office supplies through GSA but upon reviewing the same items on a site such as Amazon, there is a vast difference in price and almost always cheaper. We are unable to use sites like Amazon or other trusted websites. Sites such as Amazon can save money and disputing transactions with them is very easy. As an active online shopper who purchases multiple items each week for my own home I find many of the same items that we are being overcharged for by using GSA advantage for significantly less on other sites. Everything from boxes of paper, to binders, to toner cartridges, if we weren't so limited in where we can purchase items from can save a ton of money by shopping around more.
Additionally, if we could, we need to stop using or limiting SATO travel altogether. Time and time again, if someone shops around using various websites, people can find flights significantly less than what SATO is charging. The only advantage to SATO is that we are not charged if we need to change flights last minute, but that is minor. For example, I went on SATO to get an estimate for a flight for someone in my office to travel from DC to TX. SATO wanted to charge over $600. Upon calling the same airline that SATO was offering, I found the same flight to the same destination through them would only cost roughly $200. That's a $400 difference.
Think of the savings we would have if we weren't limited on these two fronts. A smart shopper can find good deals on reputable and trusted websites. Policy can structure what to look for and even have the procurement officer provide multiple websites for documentation purposes to show that one website's prices were better than the other, even mandating that one of those websites be GSA Advantage.
Doing this is a simple way of cutting costs in the administrative level.