Don't do it!!!!!
Well if you do do it, don't believe all their hype and rubbish. At the end of the day it's all about more money for the people at the top and as a demonstrator you are way down the bottom.
There are other party plans that are less work and give better returns. Also, while there are many 'tupperholics', you can only store so much Tupperware (which doesn't stack/next well) and it's not something that people run out of and need again semi regularly.
Sorry if this offends but I've been there done that and would have liked some of these things pointed out to me before I started.
There are positives too, but not worth it IMHO