If You're Out There http://magicletters.livejournal.com/53445.html
Summary: How do you fight back when you can't seem to find your voice? Jensen is doing his best to get by in an abusive household while protecting his younger sister, but as the bruises continue to grow deeper he doesn’t know how much more he can take. Jared is doing his best to hold them all together, until Jensen takes matters into his own hands. Suddenly thrust upon unexpected journeys, Jared and Jensen will both have to walk alone in order to discover themselves and a way back

Paved With Hearts http://cjmarlowe.livejournal.com/455486.html
Summary: Jared Padalecki has been shuffled from home to home for most of his life until one summer he's left with the black sheep of the family, his unsocial Uncle Jeff, up in the Coast Mountains of British Columbia. He unexpectedly finds a home and a family there, but when the summer's over he's torn away from it and placed with a family in the city; in return for having a good school to attend to finish his senior year, he's asked to befriend their shut-in son, a young man named Jensen who hasn't had an easy time of it either.

Taking Turns (Holding This World) http://felisblanco.livejournal.com/905038.html
Summary: When rich boy Jensen Ackles decided to get out from under his father's thumb and run away from home he didn't expect to be robbed in broad daylight, mistaken for a hooker, beaten up by a tattooed maniac and have his life saved by a really cute street kid. All in one day.

thank you !!

* Growl (http://archiveofourown.org/works/1695626) - John died on a hunt when the boys were young, and they've lived on the fringes of society ever since. (Dean/Sam)

* No Ordinary Boys (http://kc246.livejournal.com/6431.html) - Mary and John Winchester are foster parents, who take in brothers Dean and Sam. Two abused and neglected boys that end up changing the Winchesters lives forever. (gen)

These aren't Sam/Dean and don't fit the parameters, but you might enjoy them anyway, for runaway Sam and Sam-whump:

* Lux Just Ain't For Us (http://archiveofourown.org/works/1007682) - Sam couldn't go home. Lucifer couldn't go home. But that wasn't their home anymore. Their home was the shared sleeping bag under the play castle in the park. Their home was together.

* I Won't Be the Same (http://archiveofourown.org/works/2327294): In 1999, Sam Winchester runs away from home at the age of sixteen. On a bus to anywhere, he meets Lucifer, and the two weave cross-country together in a brief but passionate affair. Now, in 2014, Sam is successful, engaged, and unhappy. He makes one last-ditch attempt to find Lucifer again. He’s got no last name and no address. All he does have is an old picture and the memories of every place they went together. (Lucifer is not Satan, just a kid with a nickname.)

oo, thank you! I'm definitely open to other pairings!