In Indonesia, interbank money transfer amount and volume are very large. For each interbank money transfer, customer are charged with same transfer fee, regardless the transfer amount. For customer with low and middle economy level, they found the transfer fee quite a burden to deal with when they need to do interbank money transfer for several times per month with small amount. Flip.id came with the offer to do interbank money transfer free of charge for limited amount per day. The purpose of this study is to identify the reason of customers to use Flip.id services based on rational consumer behavior analysis. According to this study, it is known that the efficiency of using the application with significant cost reduction and the easiness of getting/spreading the information of transfer order that been done, become a major factor on why customer chose Flip.id to do interbank money transfer.