I donít have a solution for killing bamboo, but I may have one for getting it cut on the cheap.
Bamboo is a popular material for handcrafters.
Try running an ad in a local shoppers guide, such as Penny Shopper, Nickel Trader or whatever is available in your area. You might find someone who will gladly cut the bamboo at no charge to just to get it for crafting.
Even if they do not want it all, you would be that much closer to getting it all cut. Make sure you make it clear that they are expected to haul off all that they cut so you do not end up with a mess to clean up after they leave.
I have done this for a friend in the past in exchange for the bamboo. I also rake off another friendís roof and yard twice a year in exchange for the pine straw and have pulled kudzu vines from trees in exchange for the vines.
I use the bamboo and vines for baskets. And the pine straw I use as mulch for my flowerbeds.