I'll add that just a few tubers will seriously multiply! I started with 6 small tubers 2 years ago. After the first season, I had a five gallon bucket full. I replanted half of them and this year harvested a couple wheel barrows full. I know I left a lot in the ground so I expect to do just as well next year. I fed most of the harvest to pigs and
chickens.
I paid 4 dollars for the original tubers and they've produced all that food plus tons of biomass. Oddly though, none of my animals like to eat the leave even though I've read that the supposedly love them.
I can't imagine what 100 dollars worth of tubers would do to my landscape.