first of all know this-rule of thumb-
"BUYING THE WRONG PA COULD BE ONE OF THE MOST EXPENSIVE MISTAKES OF YOUR LIFE."
if you have 100$ go for logitech.you can't get near flat FQ with sub for that price.yes it's made for home use but 200w rms and sound is OK (though mid range lacks) for KB only gigs with 50-70 people.you can't get better than it for the price.bass can be more than you want so you need over all EQ  from the mixer.it's not for band music so one shouldnt compare  it to a full blown pro PA.but it does great(for the price) for above use.
dont buy nady or kustom.they simply are (mostly) crap.
I also recommand Alesis 6 ch mixer(79$)which has efx.so no cables,seperate efx box,less set up time.under 150$ you'll have more options.
the better option than stand alone KB amps is
mixer with EFX and power speakers.that's  the way to go.pwr speaker becomes your monitor when you update your system.
cheap,reasonable sound,heavy,loud for price-  
http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/600596/  and better and lighter  
http://www.zzounds.com/item--PEVPR110P    http://www.zzounds.com/item--PEVPR112P    http://www.zzounds.com/item--PEVPR115P  if your bdj is 350 t0 500$  
http://www.carvin.com/products/single.php?ItemNumber=P410-805&CID=SYS1   - now 350$,has titanium drivers,mixer has both ch and graphic EQ,
beat the hell out of custom/nady which are mostly piezo crap(esply the cheap ones)  
http://www.carvin.com/products/single.php?ItemNumber=P620-805&CID=SYS1     http://www.carvin.com/products/single.php?ItemNumber=P620-1230&CID=SYS1  if you want louder,cheaper
pwr mixer+speaker route like this  
http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/631250/    http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/601372/    http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/601374/  but if you really want to have a good sound for the price,portable,great resale value and industry standard for medium grade live sound
have a mixer with efx and   
http://www.musiciansfriend.com/srs7/g=live/search/detail/base_pid/600202/   and louder and more expensive  
http://www.zzounds.com/item--JBLEON15G2  or cheap ,but heavy for watt/weight ratio  
http://www.zzounds.com/item--JBLEON15P  go to wanted to buy and sell forum.UD is selling them for 250$ I think.good price.
if you have more  
http://www.musiciansbuy.com/live_sound_speaker_cabinets_yorkville_yorkville_elit     e_powered.html  the list goes on.
[This message has been edited by jamman (edited 01-03-2005).]