#1
Hi there. So my band will start gigging later this year. Our first show will most likely be at a high school's auditorium. The size is probably 3/4 of what you see in the following picture:


I've never performed live before so I don't really know what equipment I need. This is what I have so far:

Korina epiphone explorer bass and a 100W Acoustic amp. I know that my equipment is not nearly enough to be heard in such a large place. I don't know if I should invest in a new amp or buy a PA system. You guys are the experts so please recommend me what I need. I'm probably being optimistic, but can the equipment I need cost between $200-400?
#2
Actually 100w may be enough. An auditorium such as this one is made with acoustics in mind, and amplifies sound so that it is heard evenly throughout the venue.
#3
It is going to depend on (a.) What kind of music your band plays, and (b.) what do the other members of your band play? If you are competing with a guitarist (or two) blasting through a 100-watt halfstack, you'll need at least 300 watts to cut through.

I'd go with a bigger amplifier. A good P.A. system is a major investment. Of course, you're going to need one unless you do strictly instrumentals. What is your singer singing through?
"Maybe this world is another planet's hell?" - Aldous Huxley
#5
The school should have a PA, hook up your amp to that, but I would advise you to go used if you're getting a new amp.

Ibanez SR506BM
Ashdown Little Giant 1000w
Peavey TVX 115+410
A big ass upright