Staples, Office Depot and Office Max -- the Big 3 office supply chains -- are being hit with a double whammy at the moment. First, there have been sluggish sales because of the economy. Second, they're facing fierce competition from 3 new cheaper competitors.

Those 3 competitors are Amazon.com, Sam's Club and Costco Wholesale. In fact, Costco has opened a new offshoot chain called Costco Business Centers. According to The Wall Street Journal, there are only 9 Costco Business Centers in the entire country, yet they've already raked in $1.25 billion for the year.

The markups at the warehouse clubs are so much lower than what you find at the Big 3. Costco caps all markups at 14%. The Big 3, however, have typical markups of 28% on their products.

If you're not lucky enough to live near a Costco Business Center, Clark recommends buying your office supplies from the standard warehouse clubs and then purchasing whatever else you may need from Amazon.com.

One non-profit organization that took a similar approach was able to save $7,000 of donor money that would have otherwise gone to office supplies, The Wall Street Journal reports.

Give it a try if you're a small business owner.