i was hoping someone could recommend a good audio recording device, hopefully under $100. im using it to record my guitar (line out and mic mix) through my mixer, then onto my computer into mp3. also, im not sure if i would need to capture from 1/4 speaker outs, or do i use one of the rca jacks? this is the mixer...

Yes. Although it's only a 1/8" input for mic/line input, it will record both. The nice thing about this, is it does record to MP3 format, however you still have to pull out the MicroSD media and put it in your computer to transfer the file. Not very elegant, but it would work. The nice thing about this setup, is that it's portable. Take your mixer, recorder and instrument/mic and go mobile - record your songs, then return home and transfer them to PC.

The other solution is to connect the output from your mixer directly into a soundcard. The problem with that, is most soundcards aren't very high quality. There are manufacturers of studio grade soundcards, but I fear they're above your budget.
would there be any better/more typical way to get good results with a mixer, without connecting to a usb interface etc on the spot? like how do they actually get the mic and direct out professionally for live videos on utube etc, aside from like overdubbing later? thanks
There are better ways of doing it, but I'm afraid the cost won't be within your budget.

When I've shot videos in the past, I've recorded the audio into my mixing console/DAW, then used video software to use my audio with the video. Some camcorders also have the capability to accept an external audio input, which would certainly do away with the editing in a PC.

Perhaps try using the Line Input of your computer's soundcard. Come out of the mixer's Record out. Give it a try and see if the sound quality is good enough for what you need. You may be surprised at how it sounds - depending on the quality of the soundcard.