Laundry soap and cloth diapers...?

all the moms out there who are using cloth diapers.... ive started to use cloth diapers, disposable diapers are getting to expensive esp since i have 3 kids.. its my first time, and im clueless. ive read about all the detergents to use, what do you think is the best one and what are the prices.. please and thank you! my son has no allergy's that im aware of so... go with it