sirs, I'm using your "Membership" plugin but I after

Hi sirs,
I'm using your "Membership" plugin but I after working with it I understand that the right plugin was "Protected content".
So I'm trying to buy or download it but if I look for it after signing on with my account it seems that I have to upgrade my account spending about 99€/month while if I look for the plugin without signing on it seems that the price is 19€/month.
I'm not shure to have right understand.
Thank a lot.
Best regards
Federico