MTPowerDrums2 - it is free.
And then you can get sucked into the never ending spiral of DRAD or Drum Rompler Acquisition Disease.
"Good evening. My name is Ivan and I am a drum rompler addict. It has been six weeks and one day since I last bought a drum rompler but I still have the 853 I already bought..."
Have fun! MTPD2 is actually very good indeed, used to cost money but the developer kindly decided to set it free last year.