I have played against bowling machines quite a bit..what i can say is it helps in 3 things
1) After a long lay-off batting cage is a good place to have some hits using the "B m/c"
2) Try having the bowling machine closer let us say 18 or 16yards instead of 22 yards..this really helps in getting the timing right, helps in the quick movement of your feet and arm..
3) I know bowling machines are ok at replicating swing,spin etc but try the bouncer as this helps in watching the ball closely as you know if you miss it you will get hit so you tend to be sharp..
This way you cover 3 main aspects hand movement, footwork and getting your eye in...
Also if you can buy it is great..but you can rent as well..rental fee is usually like this
1) Separate fee for Batting cage
2) Bowling m/c with or without operator the fee varies
3) Weekends or Fri little more expensive than weekdays(minus Fri)..
Anyways Happy Batting ...as they say Smash Them