Alternative to Mod Podge?

Hi all

I want to make some of these fab comic book shoes that keep popping up on the site, but I've not been able to find Outdoor Mod Podge at a price I can afford (*sniff sniff* I ish poooooor!).

Does anyone know of a cheap alternative I can use? Alternatively, does the generic Mod Podge work ok for regular wear does anyone know? I can haunt Ebay if so!!