I never used to starch my fabric at all, but a number of people started to reccomend it, so I tried it, and I won't cut out fabric for a quilt with out starching my fabric first. I will even starch any scraps I have before I cut them out to use in a quilt, especially if they aren't going to be cut on the straight of grain.
I love Mary Ellens Best Press Starch Alternative. I have been using it for some time now. I buy the refill gallon size, and just refill my spray bottle when it runs low. The gallon sized is priced to where it's like getting two 16oz. spray bottles for free... and you don't need to buy a new spray bottle every time you run out. (I'm on my second, or is it third, gallon, and still using the first spray bottle I purchased, so the trigger handles last quite a while on these bottles. I hate the cheap ones you can purchase and they stop working after awhile). I also like the different smells, and they also have one that is unscented if you don't want any smell in your fabric.
Diane in Colorado Springs