If you get a lithium charger that's designed to charge a certain cell count at a fixed rate, they're cheap for R/C too. Typical cell phone and camera battery chargers are designed to charge the pack for that particular cell phone or camera, and no others.

The major differerence is that R/C chargers are often designed to charge any number of cells at a wide range of charge rates. Take the Astro 109 for example: 1 to 8 LiPoly cells at 0 to 8 Amps. Flexibility costs money.