From a reply to tootboy it seems that you don't have mixed lollies in the states....or milk bars
Milk bars are sort of like a small corner store also known as "the shop".
When I was a kid when mum sent me to the shop to buy milk bread and a packet of Super Mild (with a note so the milkbar owner would know that I wasn't buying cigarettes for myself) I'd sometimes get to spend the change on mixed lollies.
I checked with Mr. Blue and he also remembers uttering the words
"20 cents worth of mixed lollies please"
This was the lazy way to order, most kids would stand there, nose pressed to the glass counter watching as the Milk bar owner filled their order one, by one with his grubby fingers. I suspect they don't exist in this form anymore because of the hygiene issues. You can get mixed lollies now, but they come pre packaged so the fun of choosing them yourself is gone.
I'm sure that before and after school time was every milk bar owner's nightmare as each local kid would line up: