A decent Goodwill or Salvation Army will usually have all sorts of sizes and brands, all in one place arranged by size in most cases, and they're also cheap, of course.
A size too long might just be ok, though - I've been getting 30x30, because it seems like the right length, but my mom saw me try a pair on in a store and said she thought they were too short. I'm not sure which of us is right. (they didn't come in a 30x32, so I got that size anyways, but...)
I found a bunch of stuff on sale on the Hollister site (the only time I went into one of the stores I walked right back out because I couldn't *see* anything), but it looks like it might only go down to a 28x30? Or maybe that's just what they've got left in the couple styles I clicked on.
I like shopping for guys jeans, and I like that it's actually possible to do so online - with women's completely random seeming sizing, you never know what you'll get, but if you only try one size, it'll almost always be the wrong one. Men's? Chances are that it'll fit.