Then I guess this would be where you would have to practice restraint. CC's are not free money and shouldn't be viewed as such. Don't let yourself charge more than you can pay in full by the time the bill comes due. Remember, you are trying to build good credit, not ruin it from the get go. I know you wouldn't be here doing all of this research ahead of time, if you intended to mess things up for yourself. Keep your goal in mind and it will all work out.
Oh- and the cheapest purchase I made with a cc was at the coke machine. I was so excited I could 'blink' there. We only have a couple of places in my area that use the pay pass feature. I know, I need to get out more. 
@pdxuser wrote:
@Anonymous wrote:
The easiest thing, rather than trying to find something small to spend money on, is to simply use the card for a small purchase you would have made anyway - gas, grocery, snack, drugstore, coffeeshop, bookstore, etc etc.Or to make things even easier, set up the card to pay a monthly bill, so it'll automatically have usage every month. My Capital One card has no rewards, so I don't want to use it for normal purchases, but I set up my Netflix subscription ~$9/month for that card, so it painlessly gets monthly activity
No need to spend EXTRA money to keep the card active - just use it for an occasional purchase you would have made anyway to keep things simple.
That makes sense, of course, but I rent a room at a house, so I pay the landlord for the bills, rather than pay the bills directly. I don't drive, so there's no gas to buy, and I only buy a transit pass once a year. I make all my calls from home for free using VoIP, and I use a cell phone so infrequently that I just prepay $100 for 1000 minutes and that lasts me all year. Other than that, it's food, clothing, and other things that I know I would buy more of if I used a credit card.
I like the drugstore suggestion...how about your incidentals from a local chain drugstore? Tissues, toothpaste, floss, shampoo, etc. Think about stuff you go through, your basic consumables. And then purchase appropriately among your cards? Feeling generous? Pick up a box of licensed band-aids like Dora or Scooby-Doo and offer to a pre-schooler. Heck, maybe I'll hand individual ones out for Halloween this year... 
I've been using my Discover card for our local Red Box video rental vending machine... $1.07 per night per rental
