The trend has been around for a while, but recently they're making them with long straps so you can wear it as a cross body bag, and hold it as a clutch if you like. It's the best of both worlds.
I just snagged this one from H&M for just under $20. It looks a little summery, but I'll be wearing it into the fall.
Here are a few other choices I've found; the first two are from Scout & Catalogue.