You can freeze your yeast solid, but I think you are better off using enough glycerol to get it to freezer temps without freezing. That way the cells are as cold as you can get them, but it avoids a lot of the problems that freezing causes. For home, I think it is a good way to go. But even in the fridge it can last a long time. Rinse it a couple of times with distilled water and store it with distilled water and it should last you 6 months easily.