Cheap$kate: FREE events in NYC this weekend

R.L. Stine book signing
Don't worry if you get "Goosebumps" - it's only natural given the signing taking place today at Barnes & Noble Union Square. Just in time to kick off Halloween, R.L. Stine, the man behind the "Goosebumps" scary stories book series, will read from and discuss the first of his new spinoff series, "Planet of the Lawn Gnomes." Stine will take audience questions and sign books after the reading. (Thursday, noon, FREE, Barnes & Noble Union Square, 33 E. 17th St., 212-253-0810, bn.com)

Halloween

Screamin' Green Halloween
Get into the Halloween spirit Saturday at this earth-friendly celebration, which features games, treats, a costume swap and a parade. The World Financial Center will be made into a Halloween Village with a gigantic scarecrow and witch. (Saturday, noon-3 p.m., FREE, World Financial Center Plaza, 220 Vesey St., 212-945-0505, worldfinancialcenter.com/screamin-green-halloween)