xxxxxxxxxx
models.DecimalField( , max_digits=5, decimal_places=2)
xxxxxxxxxx
# Always use DecimalField for money.
#Even simple operations (addition, subtraction) are not immune to float rounding issues:
>>> 10.50 - 0.20
10.300000000000001
>>> Decimal('10.50') - Decimal('0.20')
Decimal('10.30')