Nebula-related works are here. Other free texts are here. Reg may be required. Also check SFWA page without reg needed. Among the goodies available for free: Two Hearts, by Peter S. Beagle. (Thanks to Garson for the pointer.)
Related: Cormac McCarthy‘s Pulitzer for a post-apocalypse novel (BBC). You can actually buy an e-book edition of The Road Amusingly, Amazon readers give this one just a four and one-half-star rating on the average, not a five. Tough customers, eh?