MIDahlias A bit of history, the roaring 20s were a time of soaring income disparity. For the well-to-do, people with the luxury of growing something other than food, that amount was not worth being concerned about, certainly not when their dahlia fever was raging, for others it would have been unthinkable.
"...income inequality increased so much during the 1920s, that by 1928, the top one percent of families received 23.9 percent of all pretax income. About 60 percent of families made less than $2,000 a year, the income level the Bureau of Labor Statistics classified as the minimum livable income for a family of five.
The economy relied on consumers being able to buy things so shoveling all the money to a tiny group of people and leaving the rest desitute was cruising for a bruising. It was a major factor that led to the Great Depression. When the dust settled, income equality was much better and remained stable until around 1980 when the 1%'s share of wealth began to head for the stars again. We are currently very near 1920s levels of income inequality. So, anyway, I think that may very well factor into how much people were paying for dahlias then. In many cases, if you could afford them at all, money was not much of an object.
