you need to consider:
all lavs, shotgun mics and wireless systems
lav- would be countryman lav. or Audio-Technica ATR3350 if there's not much wind.
shotgun- a rode ntg(1,2,3)/VideoMic, you can make your own boom pole if you have too.
so, if you're absolutely, $120 or less, get the zoom h1n and the ATR3350. If outside, use its windscreen and you can also make 2 triangles shapes out of gaffer's tape and sandwich it in between them so you don't get clothes noise. Then in adobe audition, smooth out the sound by use studio reverb at 100hz at bare minimum settings and lower the 16k. raise 192kz and 1120 hz for voice. finally use multiband compression so that the audience doesn't get a heart attack when there's a sudden increase in volume.
anything below this minimum sound quality and your video will suffer beyond the point of resuscitation no matter how well it's edited.