i was speaking from my personal exerience with bonsai...
my experience/knowledge of bonsai is that virtually any type of
tree or shrub can be used with the bonsai technique. i've never had a bonsai that was in just regular potting soil, either - and i've purchased from bonsai dealers as well as stores similar to walmart.
also, the fact that she clearly stated that the rocks were glued in place would negate the ability to water the
plant in the normal manner for houseplants (from a watering can); thus my suggestion which is as per the instructions i received every time i purchased a bonsai
tree or bush.
regardless, we digress!!
claire, what, exactly do the care instructions state? and is there a name for the company that grew it? (might want to see if they have a website as you might be able to get more information on caring for the
plant.)
also, are you sure there is no soil in the pot?
for it to have just stones doesn't make sense (unless the
plant is 'lucky bamboo', that is).
are you sure it's a money
plant? could you possibly post a pic of it?