According to a gal over at Splitcoasters:
"You can make your own glue dots by dropping blobs (any size you like) of Aleene's Tack It Over and Over glue onto waxed paper.
I did this and folded the excess waxed paper over top, once they were 'dry'.
All I have to do is open up the waxed paper, pick off one of the blobs and use like regular store-bought glue dots. They are great and way cheaper!
Also the dots can be moved before they 'set' so, if you get a wrong placement, at first, you can pick them off and move them."