Plenty of cameras have mic inputs with various levels of audio quality. Most of them don't accept large signals, so your audio subsystem must allow you to reduce its output level to avoid clipping.
If you're up for a risk you can find used camcorders on Ebay for under $100. You'll need to do plenty of research (Googling) to confirm the features and specs of one of these but you'll get a zoom lens and decent video performance. Look for a camera that uses SDHC cards for storage.
You can also choose from a few "music cameras" by Zoom and Sony. I've done some comparisons and feature checks on a few of these at my Homebrewed Music blog.
Many still cameras these days shoot video with various levels of quality and features. My preference is the Panasonic Lumix line which includes some remarkable performers, but you may already have a camera that can meet your needs if you're prepared to sync audio and video in post.
And if you have a smart phone with useful video there may be tools that improve the audio performance of the phone, like the iRig stuff, or you can sync in post.
If you're on a Mac you can use iMovie for syncing. The comparable PC program, Windows Live Movie Maker or whatever it's called these days is pretty much a dog. On the PC I've used the REAPER audio workstation software as my quick and dirty video tool, it's really excellent for syncing audio and video and trimming clips if you don't need other tools. If you need color management and such it is less useful. Here's my latest tutorial on REAPER and video:
http://www.homebrewedmusic.com/2016/...eos-in-reaper/
** Edit: Oopsie, just reread your post and saw that you're on a Mac. iMovie it is then. You can upgrade from there to Final Cut when you're ready to make your blockbuster.
There are quite a few free video tools but I haven't tried them so I can't offer any firm recommendations. Check titles like Hitfilm Express, DaVinci Resolve (if you have a very powerful PC), ShotCut, or Blender. I've worked with Avidemux a bit and blogged about it but it's rather on the techie side.
Fran