That's reason you need a decent charge with balancer. Get something from reputable company and probably the one with a monitor that let you know the voltage of each cells.
By the way, always check your Lipo cell either with Lipo cell diagnostics meter or Multimeter before you charge them. The point is you don't want to charge an damage cells ( damages cell mean it drop below 3 V almost reach 2 or 2.5 V )
I paid almost 200 $ alone for just my Lipo charger.
also
www.hobbyking.com is a good place to look for. They are pretty decent.