First off Welcome to FlowerChat....we're all glad your here!
Regarding the Dollar Stores, you'll also find FTD items at the buck stops...not a big deal in my opinion. Both companies have to sell the stuff rather than keep it in the warehouse to get it off their balance sheets.
Generally they sell to brokers, in bulk, who then turn around and sell it to the highest bidder.
Personally I would not buy them, because I do not buy any "branded" product now because I think the containers are junk, and over priced, but if you can use them and can get them for a buck...what the heck, they might be worth it ($1.00).
I'm pretty sure we'll see more and more of this going forward as more and more florists buy fewer and fewer of the codified containers. I can remember, just 5 short years ago in my store, I bought 5-10 cases of each container for each holiday. Gradually the need decreased (mostly due to decreased incoming orders, and my cutting of FTD.com from sending me orders), and today I buy none, preffering to sell items I can make more money on, and offer my customers more for their money while at the same time selling MY look, and not some cookie cutter design.