I just started using Mary Ellen's for a class I was taking. I used half of a bottle just in class alone. It is a nice product but too expensive to use continually.
Here's a homemade starch recipe I found on about.com.
1 heaping tablespoon corn starch, 1 pint cold water, 1-2 drops essential oil (optional for scent of your choice). Mix til cornstarch is completely dissolved. Put in spray bottle.
Some have mentioned keeping this in the refrigerator and shaking it each time you use it.
I haven't used this recipe but I did see it recently posted on a Board question about starch.
What is sizing?
This Board is so beneficial to my quilting. Thanks everyone.