As with other things in India, prices for priest has soared high like real estate. And there is no standard in it. They fix price based on your 'wealth' status.
Even if you go with someone, there is no guarantee that they are doing all parts of a pooja (abbreviated mantrams etc) - unless one knows in detail what are the steps and what is said/done during pooja. And who is going to tally the 1008 times?
I had good and bad experiences and also heard from others. So I have started doing some homework before any job and try to know in its entirety and then go with the priest. This cautions them to be careful with us.
Only few priests do it sincerely, rest of them are for business, and do not even turn off their cellphones during pooja. They don't want to lose clients.
Regarding prices:
1. 4 priest along with head priest chanting mantras will sound good. However, prices increase. 1500 Rs per head is bit high. Head priest may get 2500 - 3000 Rs in this case. Sometimes, they bring in teen kids who are trainees to chant mantra as much as they can.
2. Homam materials hardly cost 300 - 500 Rs. They regularly buy from their source at a cheaper rate.
So bottomline finding a reliable priest cost wise and ethical is a challenge. Even if you find one, if it happens to be a busy season and other factors, for him to do a proper pooja is at his discretion. Kali kalaam!!