Free item when you buy a different item?

I usually never use the coupons that are for a free item when you buy some amount of a different item. Example: "Buy 2 loaves of bread and get one milk for free". Typically, I dont want both of the items that the coupon makes you buy to cash in on the deal.

In this week's paper (or maybe last weeks?) there was a coupon where you could get a free Duncan Hines cake mix, if you bought 2 cans of the Duncan Heinz Comstock pie filling. Sweet! I anticipate baking many a delicious treat in the coming months so I have been scouring the coupon world for deals. Here is what I bought:

The cans of pie filling were on sale for $2.99 (still kinda pricey if you ask me!), but had a peel off coupon attached to them to save $1.00. So, for $4 I bought two cans of cherry filling and got a free box of the Duncan Heinz cake mix. Sweet success!