Great thread!
Well, this might sound gross (my boyfriend is super frugal but he doesn't do this) but I re-use my coffee grounds. Since I use the gold filter (not paper) I just leave the grounds in there for the next day, add half the amount of coffee for the # cups I want and put my coffeepot on the feature (I think it's intended for making four cups or less) that double-heats the water.
I usually use Folger's or Chock Full 'o Nuts coffee since the cheaper brands seem to upset my stomach. Since my re-used grounds taste fine to me, it's my way of offsetting the price difference. Just don't re-use the grounds too many days in a row, especially in the warmer months!
Oh, and I know you asked about ways to stretch items so I guess this is a little off-topic, but I buy the bigger bottles of green Palmolive dish soap when they're on sale. I've got a big ceramic dispenser from Target near my kitchen sink and another in the bathroom so I fill them both up with Palmolive and it lasts a long time.
We also have cut out things like restaurant food of any kind and things like pop, just drink water or juice from concentrate, occasionally Kool-Aid too but that leaves me craving sugar. And my son is making all the cookies for his lunch these days, we're not buying granola bars or anything lately. I've also become less of a toilet paper snob and found the four-pack our Kroger store puts on sale for 89 cents is actually not the end of the world and though it seems thin, actually lasts longer than the "good stuff".
My boyfriend and I split our cell phone plan and are scrupulous about not running over more than about 500 minutes we share each month. We also buy larger packages of Ivory soap bars or a big bag of rice or a 10-pound bag of chicken leg quarters and divide the cost.
For laundry soap, I buy the big dispenser jug of Surf/All (or whatever they're calling it these days). It's cheaper than smaller bottles overall and lasts forever.
I also try to make something like banana bread to eat breakfast on the road so I'm not tempted to swing by Tim Horton's! Thank goodness my car gets 30 mpg, that helps a lot! : )