I one found - and bought for my BL - a PAIR of used Peavey SP4's for $600.
We used them for about a year and powered them with a Behringer iNuke 6000 ($349).
That alone will handle most clubs/bars you'll hit..
If you want to add in subs later... so be it.
There ARE deals on CL - as there are on evilbay... one needs to be vigilant, patient and as @Omega Monkey said, be ready to pounce and have some cash available.
I own about $25k of PA gear, bought piece-meal with
cash. NO DEBT!!
Mics (SM57, SM58, i5, e609, E835, D6, D112, etc.), 4 consoles (1 digital), bi-amped tops (modded Peavey SP2's with selenium horns), Yorkville powered subs, QSC, Crown and Yammy power amps for high, mids and 6 monitor mixes, 24x8/16x4 + various drop snakes, DRPA+, Yammy wedges, and so on - ALL bought for WAY less than retail.
Most of it sits idle

as there is no market for SR these days.. all corporate level in my area... small independents like are basically non-existent, and I'm too busy playing now to provide SR for bands...