not sure what scalper prices will be like this year since prices on tickets went up and seating sections were re-assigend/redefined.
If it's a sell out, you're lucky to find anything near face value but look for a while first 'cause there's always guys with seaso ntickets that couldn't find someone to go with or got the tix for free and they don't realy care, etc... If it's a cheap game, not that much interest, like when the Rockies or Marlins come to town, you can get them prety cheap. Sometimes a pair for the face value of one.
Just check out the dodgers site for the actual prices and seating sections. Once you get there compare the scalpers prices with the real prices and decide whether it's worth it.