I'd be interested to hear why you say you can't say no. You mentioned it pays more.. that in itself isn't a good reason to back out of the first; but if you're incredibly broke and this means the difference between paying rent, or not, I can understand the dilemma. He's a former teacher; do you feel that obligated? Maybe we, here on TM, can help you find a sub? I notice from you're profile, you're either in Columbus or Buffalo. Backing out, if you've found a good sub, is OK... just make sure s/he can do the job.