They pay three times the price and six times the wholesale price. They are the same berries, harvested the exact same way.
You can double the price again, if you have someone hand pick them instead of raking them. Even better, you can charge them about the same price and let them pick the berries themselves.
This comes up with some regularity in my circle of friends. They've been sold the idea that the value of exercise is only measured in terms of calories burned per minute of activity. Not only is this negating 90% of the benefits for exercise, it's also a useless measure because it's impossible to out-train a bad diet and excess calories.
The thing is, this only applies during high-level competitions, and in no way counts for the rest of the time. Nobody can compete at that level endlessly, obvious. More importantly, it doesn't raise their basal metabolism beyond a certain point, and the basal metabolism is what counts in overall long-term caloric consumption.
For regular humans, there's simply no getting around the fact that running a mile only burns 100 kCal or so[1], and it's possible to eat more than 100kCal in seconds simply by eating a single Reese's peanut butter cup[2].
1. http://running.competitor.com/2015/03/training/many-calories...
2. https://www.hersheys.com/reeses/en_us/products/reeses-peanut...