CoyoteMagic was kind enough to post her method for using Elmer's washable school glue to baste her quilts. Here is a link to the thread (note: the Elmer's *adhesive* in the title is not the same as the Elmer's school glue):
http://www.quiltingboard.com/main-f1...t-t180790.html
The description of this method is at the top of page 6 of this thread.
There are lots of homemade spray starch recipes on the QB and on the net. If you Google, you will find them. Aside from the Sta-Flo and water combo that Kitsie mentioned, you can also simply mix cornstarch and water (or potato starch and water; not all starches used for fabric need to be corn-based). These homemade starches don't contain preservatives, so you usually want to keep them refrigerated and mix up only small batches at a time, as they don't last more than 2 weeks or so before becoming moldy.
There is also a non-aerosol spray starch on the market. Several people mentioned getting theirs at Walmart, I think.