My
LFS sells for $0.25 for
FW and $0.75 for
SW. Machines outside the local gorcery stores sell for $0.25 as well. You probably pay $2 inside per gallon. There has to be water refilling machines (don't know what they are called) outside or inside your local grocery store.
If you have a Costco, they have
RO/
DI units there for good prices that are reliable and use replaceable filter cansiters.