Hope this gives you some answers:
Guide To BuzzerBeater + FAQ (144856.13)
Salary
5 balls = $3,700 and higher
4 balls = $2,800 - $3,700
3 balls = $2,300 - $2,800
2 balls = $1,900 - $2,300
1 ball = $1,900 and lower
Potential
5 balls = 10 - 12 (MVP - All-time Great)
4 balls = 8 - 9 (Perennial Allstar - Superstar)
3 balls = 5 - 7 (Star - Allstar)
2 balls = 3 - 4 (6th Man - Starter)
1 ball = 1 - 2 (Announcer - Role Player)
Informal Draft Guide (120597.31)
A+ = 4500+ (I have seen rookies with a 6k starting salary before)
A = 4200 - 4500
A- = 3900- 4200
B+ = 3600-3900
B = 3300-3600
B- = 2900-3300
Informal Draft Guide (120597.1)
A+ > A > A- for A+ (+5000K) A (4500k) A- (3700-4500)
B+ > B > B-
C+ > C > C-
D+ > D > D-
F+ > F > F-