The only thing I do that could really be considered cheap is making my friends/housemates pay when they do things like printing from my printer, use my stamps...
I wouldn't mind doing nothing... but there is a habit around here where if I buy something, they seem to have a sense of entitlement to it and don't bother buying their own. They think I'm an ass because I make them pay for printing... but they also think I'm an ass if, instead, we split the cost of a new toner cartridge. :roll:
When I'm on vacation, if the hotel ever offers a "free breakfast" and they have the small boxes of cereal, I take a few of them and eat them as snacks later.
I re-fill bottles of water and put them in the fridge. I don't care about bottled water. I care about having a nice cold bottle of water.
80% of my clothes come from thrift stores. It's not that I like paying 50 cents for a shirt... it's that I like NOT paying $50 for it.
When I was living in the dorms, my roommate and I would just swipe one of the giagantic rolls of toilet paper from one of the campus bathrooms instead of buying it. We mostly did this after realizing that every girl in the dorm always seemed to want to borrow a roll of toilet paper and never return the favor. Like I'm going to go knocking on someone's door... "Hey.. you know how we gave you a roll of TP? Yeah... I'm gonna need that back."