Archie's Gold a juvenile/middle grade mystery by E.R. Yatscoff

http://www.amazon.com/dp/B005E1PEFQ
 
Get back to true grit and reality.  No vampires, zombies, aliens, wise creatures, or parallel worlds.  My boys get in trouble they must get out using their brains, not magic wands.

Twelve year old Archie Crane has a dream to be reunited with his estranged father, and shining shoes  in front of a hotel in a tough blue-collar town is the only way.  Every nickel and dime dropped in his can goes toward a bus ticket to leave his mom and sister.  The mean streets get a whole lot meaner when Boogy, a local rink rat, is determined to wrest the shoe-shine spot away from Archie by any means.  After one busy night riding his bike home, Boogy pushes him into traffic.  Archie awakens in the hospital with two detectives at his bedside, very curious as to how a stolen gold coin ended up in his money can. 

It's a mystery to Archie, too.  Looking like a failed lab experiment from his injuries, Archie pedals his smashed bike around town trying to discover the mystery of the coin while fighting off Boogy.  One stolen gold coin is a curiosity, but when Archie stumbles upon 42 of them, his simple world is turned upside down.  The two cops catch gold fever, determined to find all the coins.  Caught between holding stolen coins and finding someone trustworthy to turn the coins into cash proves difficult and dangerous.  Enlisting the aid of an ex-con might be a bad idea, but he's running out of time.  As the walls begin to tumble and the police close in,  Archie's hope of rejoining his father may only be a dream. 
yatscoffbooks.com