sound-dept What sound gear do I need?

I have a really tight budget, like $70 for audio max. I am looking for a good microphone, but I've never been very good at dealing with the audio side of production. I am shooting on my phone. I don't need amazing quality, but I would like the best quality you can get for that budget. Do you have any suggestions? What type of microphone should I use? I don't know much about audio, so I'm kind of lost with all the different types. Thanks for the help!
It all depends upon what you are shooting. If you are doing interviews you could get a pair of cheap lavs. If you are doing man-on-the-street interviews a handheld interview mic would work okay. Otherwise you might want to put a shotgun or hypercardioid mic on a homemade boom-pole.

Additional details on your project needs would be appreciated.
Its something cheap that I still use for small productions. Alclcove is also right. It depends what you want to make. I think the Zoom H1 would also work as a Hand mike if you can build a selfie stick with a shock mount .....or something. The good thing about this set would be.....its really easy to use, around 70,- and flexible for more than one situation. Also you will still use it when you upgrade you film kit. Its also something that will let you learn a lot about sound.

There are many ways to get around your budget issues. Rode and a few others have "production" mics that can be plugged into a smart phone (you'll need a decent app for recording audio). Mount it on a painters pole and away you go.

I would also suggest that you look around for someone like yourself who is starting out, but wants to get into sound-for-picture. They might even have some gear already, so you could possibly save yourself a few ducats there.

Production sound is very easy to get wrong, but not too difficult to get right. Having one person whose sole job on-set is production sound and ONLY production sound will have a very positive impact on your project.

I would suggest that you read "The Location Sound Bible" by Ric Viers; a great place to start.