I'd like to recommend Merchant Prince of Arcadia--a 'classic' style SF story about a young space merchant marooned on a medieval-technology planet. A technology degree and military background would be more helpful, but Jake was an ancient literature major--not much use. Still, if he's going to survive, he'll need to work his way up from being a beer barrel washer. Maybe culture and trading really can trump military might???

It's a full-length SF novel, released in April, 2005, and only $1 from www.booksforabuck.com. Here's a URL:
http://www.booksforabuck.com/sfpages/sf_05/merchant_prince_arcadia.html