Yes. In my experience cardboard better than newspaper. Shredded office paper is good too.

The downside of paper is that it tends to turn into soggy clumps. I wouldn't avoid using it, but try to find another brown. If you are just doing a small amount of composting, consider getting a bag of wood pellets from a feed supply or big box store. (They are used as fuel in wood stoves and as animal bedding.) You can get a big bag for about $5, and then whenever you add kitchen scraps just add a corresponding scoop of wood pellets.

In the fall, go trolling in the suburbs for bags of leaves left at the curb. After a few weekends you can have a year's supply of brown material for composting. Added bonus: leaves have nutrients drawn from deep in the earth that you would otherwise have to pay big bucks to add to your garden. All for free.

One downside to using paper as your source of Carbon is that it has no nutrients.

kimmq is kimmsr

Sawdust or finely chipped wood can work well too. A little goes a long way, obviously not from treated wood (eg from a felled tree is fine. )

Newspaper or cardboard offers quite a lot of C for the weight:

http://compost.css.cornell.edu/chemistry.html

If these things are easy for you to get, and dry leaves are hard for you to get, then I would not let lack of minerals etc. in the material be a reason not to use cardboard and newspaper. If you are composting on an urban scale, and using the compost on an urban scale (i.e. small garden or containers) it is not difficult or expensive to make up for a hypothetical lack of minerals in other ways. Of course, everyone on this board would hasten to remind you that unless a soil test shows an actual deficiency, going to extra lengths to supply minerals is needless effort and expense.

These days, I find corrugated cardboard in much more plentiful supply than newspaper. I haven't subscribed to a newspaper since 1998 or so, because Internet, and even advertising circulars and free city papers aren't what they once were, but OTOH Amazon deliveries and the like sure generate a lot of cardboard. I also have most of my groceries delivered and those come in cardboard boxes. Corrugated cardboard doesn't mat down or form soggy clumps in quite the same way that newspaper can, but it helps a lot to shred it or tear it up as finely as you can. A household paper shredder that is rated for a high number of sheets can often shred cardboard for you, if it's not too thick and if you are careful to cut or tear it up into pieces first.

For vermicomposting, or cold composting, or the cold final phase of hot composting, you will also find that worms really go for corrugated cardboard, because it is generally made with a cornstarch glue to attach the layers together and worms love the carbohydrate.

I live in an urban area too, garden on a tiny scale, don't own a car, and don't have physical capacity to do hauling or heavy lifting on my own. So I can relate. But even folks in the leafy suburbs generally only have autumn leaves available once a year. :-) As another poster suggested, you can make an expedition to the suburbs and gather all the leaf bags off the curb that you'd like - IF you have enough storage space to keep them on hand to supply yourself throughout the year. And if you have a car. (I use Zipcar on an as-needed basis, which is convenient yet spares me much of the expense and all of the hassle of urban car ownership.)

If you have absolutely no shame (I don't) there are also street trees, which drop lots of leaves on the sidewalks in the autumn. If you have a small rake, a granny cart, and a bag you're in business.

You can also check to see what your city or municipality offers for free to residents. Public works departments/streets departments often have free shredded leaves for pick-up (on a seasonal basis) in addition to wood chips.

Thank you all for the helpful tips. I will use cardboard as main source of C as no easy access to leaves/grass clippings.