Hey guys

I have kind of a unique situation for the next week and a bit. This week is reading week for my University (kinda like our March break, but in Feb). I live in rez, and am the only one staying on the entire floor. I am staying the week to get homework done, but I also would like to record a bit, since it will be so quiet.
I could record in my room, but it does not have the greatest acoustics ever. The hallways, however, are pretty sweet. They are made out of concrete and my guitar's have always sounded better in the hall. I was thinking of doing the recordings in the hallway (since 1.) I wont get into trouble cause I work here and 2.) no one is here to complain). So my questions are:

1.) Will recording in a concrete hallway with high celings through a usb mic using audacity work? Will it sound cool or just dumb?

2.) Is there any good mics that I could use on my compuer under, lets say, $75 Cdn? $100 Cdn?

3.) My equipment is a Epiphone Sheraton II plugged into a Fender Hot Rod Deluxe III, and an acoustic guitar, and my voice. I play folk music, so obvthe electric is using a clean tone.

Thanks guys, I am just getting into recording so, sorry about noob questions!