nah, not really that expensive. I just checked
www.partsamerica.com, and they list a head gasket for that truck at about $35. now granted, prices vary from place to place (im in central Ohio) but whereever zampolit is the price shouldnt be more than $50 for a single head gasket. IF (and I should stress IF) that is all that is wrong is just one blown head gasket, then I would think you could get it replaced by a reputable mechanic for $150-$200, parts and labor.
However, you may want to consider getting both heads done, meaning removal of both heads, and a complete valve job done on them while they are off. That is, if a) the truck is still in decent enough shape to warrant putting the extra cash into and b) you plan on keeping it for a while longer (like 2+ years). Of course, this extra work will cost you quite a bit more (probably in the neighborhood of $800-$1000 for everything. but compared to buying a new truck, thats pocket change.