Other suggestion- buy very small, healthy, cheap plants at a big store. Many can grow much bigger, they are just cheap because they are small.
Buy a lemon, make lemonade, and plant those seeds.
You might even ask for a cutting if you find a big rangy plant in an office, library, etc.. I have given out a couple. If the place has a plant lover, she or he may be delighted to share (before the plant overtakes the place)
