Danny, if you want this amount of tigers and hemp, you should prepare them yourself and save bundles. I bought a 20k sack 3 years ago and I'm only half way through them. Be careful with the prep work and follow the guidelines to the hilt and you'll be fine.
I think me and the Monk did an article on particle preperation - I'll have a look.
alternartivley to pet stores, try farm shops that sell horse feed. There is one that i go to that sells 20kg bags of hemp for ?15. They also do loads of other stuff too....vitalin, crumb/cereal. Dog/Cat Food! loads of potentially cheap baits!