Becoming a doula

So I know you don't have to be certified to be a doula, but I'd like to take an online course. Originally I was looking at birth arts international, I could take birth and post partum courses online for $670. However, there's a group near where I live that offers online doula courses for both birth and post partum for $550, that'll save me $100. Plus I learn about breastfeeding, nutrition, and business. Its called doula alliance. Just didn't know if it mattered or not?