Do you BUY coupons?

When I first started seriously couponing, the idea of buying coupons of the internet seemed crazy.  However, the more I thought about it, it can make a lot of sense and be a good use of your time and money.
You can check Ebay, and many other sources for purchasing coupons online.  You need to be careful!  Do you really need 20 BBQ sauce coupons that expire in 3 weeks?  My general rules are I buy coupons online when:

• The coupon is for a product my family uses frequently 
• The item can be stock piled easily
• The coupon will result in a free or deeply discounted product after use.

Do you buy coupons online?