Sometimes my friend mixes 50/50 with tobacco if he only wants to use a little bit of some really strong weed. It's only like .3g, which is not really enough to physically roll a good joint, but if it's top quality stuff, then it's still enough to get totally baked. The tobacco helps form the joint when youre not using much weed and helps it burn.

Personally, I save the good stuff for the glass and put straight mids into paper.