Usually between 400 to 1000 dollars depending on amature experience. Most of the guys I know started out at a 400 and 500 hundred their first 5 or 6 fights, but I've heard of guys making up to a 1000 for there debut. Average boxer, of course. This is also before taxes and whatever else has to be deducted.
SRL made $40K his first fight. Of course, he's not the average boxer. I remember Larry Holmes saying he made $300 for his first fight.
Nowadays... most of the low level boxers at least around here make around $350 - $500 a fight when they start out.
It doesn't matter ... anything more than $10 in less than an hours worth of work is good to me ... and you get to beat someone up --
Kid Thunder, Charlie Zelenoff's opponent, is payed $400 for their fight... It's a career high payday... http://www.boxrec.com/list_bouts.php?human_id=260189&cat=boxer