It is ideal if one can afford all three. However, this is probably not the case with the majority of affiliates.
So, for new members I would recommend IAHBE while still learning, if they have no previous knowledge and experience with online business.
When they have worked out how the system works and are ready to act, it will be good to change SO to TCredits.
Another change may proceed, this time to S-Builder, if they see little or no result from their recruitment efforts. Or, if they can afford, add it to TCredits 125 pack.
If their budget is tight, there is a load of suggestions at Ask SC previous questions.