Uhhh... when I checked on the tool it was like $240.

There are ways to make your own from hardware-store parts. It does not catch the flywheel teeth but uses one of the bolts that attaches the spider to the torque converter. You remove the bolt and screw this tool in its place and it catches the trans housing, thus stopping the rotation of the motor. Let me know if you want more information. Some time ago I wrote up how to do it so it's in the forum here. If you search on 'flywheel lock' you'll find it.