It is possible that you may not have sufficient amount to pay for the package that promises to get you good reviews and good ratings for your app. It does not mean that you should refrain from availing the services from the package. You could think about lending money from friends or from your close family members. But, here you have the problem of repaying them immediately either in a month or two months. How about availing the right payment option that is available on the website that is letting you avail the packages so as to meet the google play marketing requirements?
How about paying the fee that is charged for the package with the use of the credit card? Definitely you would have the option of converting the transaction into installments that could be paid out in easy installments say in the tenure of 6 months or 9 months or 12 months depending on your repaying capability. Make sure that you select the tenure assuming that your app would not hit success in the play store so that you could set the installment amount to the extent that is repayable by you. If at all the app gives you good success you could clear off the total amount by clearing the installments that is taken on the credit card for the transaction made by you on the website.
Also, when you avail the credit card payment option you do not have to let anyone else know that you are lending money for the purpose of promoting the app. This does show that you are wasting your money on the app promotion. Paying this way using the credit card would also let you avoid quarrelling with your family members for the reason that you are investing on the app that is not trusted by them.