add up the price of everything needed to end up with a functioning tank with just live rock. ask for the tank from mom and other bits and peices from other people for X-mas. If that works get it set up and cycle your rock.
Maybe after a few months of proving that you are not in a phase and she sees the tank growing and maturing then you can hit her up for some fish cash.
Followed after months of keeping them alive with some coral.
Believe it or not but just watching the rock come back to life can be very rewarding.
After months of this if it turns out that it was aphase and you dont want to keep up with it you can sell off the rock and tank pretty easy and no harm no foul
Maybe after a few months of proving that you are not in a phase and she sees the tank growing and maturing then you can hit her up for some fish cash.
Followed after months of keeping them alive with some coral.
Believe it or not but just watching the rock come back to life can be very rewarding.
After months of this if it turns out that it was aphase and you dont want to keep up with it you can sell off the rock and tank pretty easy and no harm no foul