I'm currently reading a book called Odd Man Out by Matt McCarthy, ex-pitcher for the Provo Angels (rookie league team for Anaheim). In his season with the club, back in 2002, his salary was $600 a month, from which $30 was deducted to cover the laundry detergent needed to wash his uniform. There were also fines assessed for missed workouts, paid to the conditioning coach, who pocketed them. McCarthy's conditioning coach saved up the fines and spent them on strip clubs in Canada. On the other hand, the head coach of the team, Tom Kotchman (father of Casey), paid out of his own pocket for the starting pitcher of a road opener to fly to the destination city so that he could get some sleep before the start, rather than spending all night on the team bus. Tom Kotchman still manages the team, although they've moved and are now called the Orem Owlz.
At least in 2002, the minimum signing bonus was $1,000. McCarthy got that after being drafted in the 26th round; so did his best friend in college, Craig Breslow, now a top-notch major league reliever.
Back in '02 rookie ball rosters had 30 guys but now I think it is 40.
Players paid for their own lodging while living in the home city. In McCarthy's case, the Marriott hotel cut a deal with the team to charge only $40 a night for rooms, but even so, that's double a player's salary right there. McCarthy lucked out: a host family took him in for free.