I most definitely intend to treat the room and understand the importance of it. However, being a college student just trying to make ends meet, I don't think I can afford $400 all at once. For now, recording vocals is probably the most important aspect I need to tackle as far as getting things sounding as good as possible. So, whether that means recording in a closet or making some sort of makeshift booth or barrier until I can afford to treat the room completely, any suggestions would be much appreciated.
Ok, well your budget, is going to be the crutch, that will make it really tough to get what you are wanting/expecting.
Please, do not even think about going into a closet, for quality vocal tracks. That is likely the most highly ridiculous thing, that Youtube videos/internet BS, has ever promoted. The absolute
only benefit of using a smaller space to record vocals, is if there is some need to hide from outside noises, or feel embarrassed singing in front of others. Either way, the amount of treatment/isolation expense, to make this actually work well, would be likely $3,000, if the space was even large enough to make it happen.
Regarding the 'makeshift booth, or barrier', there are many threads about reflection filters, that many have had good things to say about. This is however, not going to make your room sound better, while mixing. Probably help a bunch with the actual recording of your vocals, but you are still in the same (most UN-desireable) room.
You could build two of the panels that I did, and hang them from the ceiling, or mount them on mic stands, for the price you would spend on one of these 'Reflection Filters'. I actually still use this technique in my studio, even though the room is already treated. I just take two of the panels from my drum room, to place in this scenario. Then, you are two panels further, into getting it right from the start.
Look at the pics on my website. You can kind of see what I am doing there.