Trading work for lessons is pretty common around here. Just remember they probably have quite a few people wanting to do the same thing so depending on your experience you may have difficulty finding somewhere that has available work.
If making calls/emails doesn't work out try advertising for odd jobs around the neighborhood. I mowed lawns, shoveled snow off sidewalks, painted fences, cleaned tack etc. Anything I could find to make up money for lessons. It was hard work and sometimes I could only afford a lesson or 2 per month but I found it so worth it.
I feel your pain and hope everything works out for you!