What software do you use to record and mix? how much gear do you need? it seems like you'd need a fairly sophisticated studio to do foley.

I use Pro Tools, and it’s pretty much the industry standard for recording, editing, and mixing.

Professional foley stages are very sophisticated. They are sound isolated and quiet, and are often purpose-built for foley in that they have a number of floor surfaces and pits, and some have moveable panels to change the reflectiveness of the room. To get good sounding cement floors, concrete has to be poured several feet down, ideally through the foundation to the dirt. Building great sounding wood floors is not easy either. There are contractors who specialize in constructing foley stages, and good ones can cost hundreds of thousands or even millions of dollars.

That being said, there is a heck of a lot you can do on your own with a decent mic, either outside or in a quiet room or closet in your house. You can get a good stereo recorder for a few hundred dollars that will allow you to record all sorts of stuff. That’s really all you need to get started. I have the Sony PCM-D50 and it’s great, but there are lots of other choices for far cheaper. I use it all the time when doing personal projects or to pick up a sound that’s missing on a show I’m working on.

You definitely don’t need thousands of dollars of gear to make great, useable recordings.