Mutt System
Built my trail rig system pretty much on used gear, not recommended for the faint of heart but here goes, and I dont have any complaints.
Head Unit: Aiwa from BestBuy, CD, MP3 and has built in subwoofer crosover for easy addition of sub to system. $149.00
Front speakers: Infinity something or others, floor model from a sound shop (eBay) they have adjustable tweeters. $35 plus shipping, also ran some inline capasitors on front speakers to keep bass out of them pretty much. $30
Rear speakers: Polk 6X9 3-way something or others (eBay) $20 plus shipping.
Amp: Older Crunch PowerZone bridged to one channel, something like 250 warts RMS, nice cheap American Made amp, lots of crossover and bridging options. (eBay) $65 plus shipping.
Sub: Old Rockford Fosgate Punch 12 eBay) much better than most of the new stuff RF is putting out. $40 shipped, plus a sub box kit from local audio shop $40.
Wiring and such came from inexpensive amp wiring kit.
The Aiwa deck runs the 4 main speakers just fine for me and with the seperate built-in sub crossover I can adjust the bass, midbass, mid and trebble all from the head unit, makes it pretty easy system to set-up, almost no distortion even at full volume.
System is in no way bling bling, but it gets the job done for a vehicle I'm not in that much.
I have much more complicated multi-amp system in another vehicle and it does sound better, but the above system was ALOT cheaper. Just remember, sometimes simpler is better if its just for you and not to show off.