100 hours in a Jet Ranger would cost more than 200 hours in an R22 and it wouldn't be enough to give you a commercial licence and therefore you wouldn't get paid for any work, therefore, no job with school!!
To instruct, you need at least 250 hours plus a 30 hour course plus CPL/ATPL theory. If you actually want to get paid for this instructing, you will also need to hold a CPL.
Cheers
Whirls