I have the same problem. New house, no mature trees therefore no leaves, etc. I've been bringing home the used paper towels from the bathrooms at work.
You do want a brown to green ratio of 30 to one I believe, although I'm no expert...
Maybe paper scrap from junk mail, etc.?

I'm always short of browns in the summer too.

I also use paper from around the house. I shred mail and paste board boxes. I cut up news paper. I have a separate kitchen waste can for paper towels and paper plates from the microwave.

My pile is frozen Dec to March so, I bag this stuff all winter and then use it in the pile as the greens go in.

"I've been bringing home the used paper towels from the bathrooms at work. "

I'm not sure that's such a good idea. Those towels could have all sorts of bad things on them. You'd be better off getting the shredded paper from work. Or if they don't shred, just take the discarded reports and shred them yourself.

Yea, I was a little concerned about the used paper towels at first. But they are only used to dry wet hands off, and even if someone is blowing their nose into them, does it matter? I mean it's only going in the compost bin to break down. Plus they are pure %100 recycled paper towels, no bleach, chemicals etc.
Miketa, how about dryer lint? Not sure about the chemicals though from the fabrics, etc.
That's a good idea about the discarded paper reports from work. I guess that greenbar computer paper is safe?

Any local farms you can pick up some bales of straw from? I have my eye on a couple of the large round bales that have been sitting on the edge of a field since last fall. A couple of the strings have apparently broken and the bale can't be picked up with a tractor. I'm thinking if I could somehow drag it onto my trailer I would have a great source of browns. Quite often farmers are trying to get rid of last years straw before they start this years harvest and in many cases just burn the bales.

Lloyd

The largest source of browns in my pile is shredded junk mail. I get tons of junk mail and am happy to make something useful out of it.

I work at an insurance office and we shread documents often, but it's still not as much brown as I want. I'm thinking of going to attorney's offices, accounting offices, etc. and see if I can get their shredded paper or just look in the dumpster outside an office complex. I live in a large city with lots of offices. Some of you may not have the same opportunity.
I've also heard of going to places where they have sawdust, but make sure it's untreated wood. Some cities might give away chipped yard
debris?

I have a tree that drops TONS of leaves!
I also have a new compost bin so I hauled my old one over near the tree and have filled it half way with leaves I didn't get to last year.
Now I have a bin of browns to add to the new bin when I need to.
Check out local gardeners who trim bushes and trees. Those leaves go brown after they've been cut.
Check out those gardeners! I'm sure they aren't making compost heaps or bins! They're just hauling it to the landfill composting pile (which charges you to dump AND charges you to buy the compost!) Maybe you can strike a deal! HTH Nancy

just be sure if going to woodworking shops that the sawdust you're getting is also not from plywood. i work in a cabinetmaking shop and most of the work we (and most woodworkers) do uses plywood. i grill my boss about what's in the bags before i'll take it home. the problem with plywood is the formaldehyde, and possibly other unwanted chemicals.

Cardboard is a wonderful brown, & there's always a ton of it in dumpsters.

Retail places that stock often, like dollar stores & grocery stores, are good sources, & there's a Long John Silver's restaurant near me that must sell a lot of fish; I get a trunk full of cardboard every time I go by there.

Check inside the store first, before you start "dumpster diving".
The dollar store near me breaks down its boxes & stacks them on a trolley, taking them to the dumpster when the trolley is full.

If I happen to get there before the trolley is full, I just load the cardboard into a shopping cart & put it in my car.

It's much more comfortable inside the air-conditioned or heated store than out on the parking lot!

To compost cardboard more quickly, tear it into smaller pieces;
you don't have to shred it, but the more surface area, the faster it'll break down.

(& cardboard composts faster than paper, since it has air cells between the layers, while you have to be vigilant to keep paper from packing down.)