What kind of PA equipment does my band need?

I'm starting a hardcore band (stuff like old Thrice, Oh Sleeper, Refused, Greeley Estates, etc) and I need to get some mics and PA equipment, but I don't know what I need. We are just starting out and I don't know if it will necessarily work out so i don't want to go out and spend like $1000 on a PA system that is only going to be used for a little bit. For now while we are just a garage band I just need something that can let us practice but at a very low price. Any suggestions? Also, where can I get it? and how much?