The reality is the credit line is way better, easy admin, lower cost and you don't lose your "opportunity cost".
And they have a HUGE industry providing these commerical financing packages, most have a department solely concentrating on the manufacturing sector.
But paying 4 each month, depending on the AR turnover days, the interest rate could be as high as 48% for a 30 day turnover, and as low as 16% for a 90 day turnover rate.
last time I checked, 16% is credit card territory.