Hello moms! I have such a question... The baby has been on IV since 1 …

Hello moms! I have such a question... The baby has been on IV since 1 month, we've had so much trouble choosing the formula (tried Nan, Nusilion, Similac) from all the formulas, the child had rashes on his face. After trying Nanni, everything went away! We've been eating Nanni Classic for 4 months now. But now this formula is not in our budget. Can you suggest what kind of formula (more affordable) can we switch the baby to? He is 6 months old now.