I think that an Aerogarden would be a great gift for parents. It's really easy, comes with it's own nutrients that i believe are ph buffered, lights, reflector, timers... plug n play. Order forms for seed kits and fertilizer pellets, and of course, tech support and warranty. Plus, good ol' Mum can reap the benefits of scientific horticulture without a second thought. Old people just can't get over how fast shit grows in hydro.
I do think it is a waste of money for growing cannabis, as it's just not suitable for such a large plant with such high lighting demands. You can build the rubbermaid tub above and get a 150w HPS for cheaper, and spend way less time attacking you plants with clippers every day.