welcome to audiofourms.com...
i would suggest a 16 channel mixer,
(i just purchased a soundcraft GB2 16 channel mixer for a project at my work and am quite inpressed with the quality vs cost)
dynamic microphones are a must.
the o'l stand by is the shure sm58
(the microphones last forever)
build your own cables...
(canare 4 conductor shielded cable is superior. use neutrik connectors for balanced cables)
you should get at least 2 amplifiers..
(one for your mains and one for monitors gives you 4 channels of signal amplification)
assuming you are going to use a passive system.
(QSC makes the best low end amplifiers for the money. The RMX series)
and i have hears good things about Kustom Audio in regards to speakers
as for costs,
you are looking at spending at least 5k to get yourself into a good professional system.
Enjoy the Silence.....