When we see something in the script written as "10 and 6" or "7 and 5" and so forth, what is essentially being stated is that the cost of this item is 10 pengo and 6 filler. This would be similar to us saying 10 dollars and 6 cents.
When Ilona says "Fourteen-and-four - fourteen-and-five - fifteen -", she is counting out the customer's change to them, adding up to fifteen. What she says aloud would equivocate to 1 bill (10-note) and 8 coins (two 2-pengo coins, one 1-pengo coin, and 5 one "cent" coins).
The pengo came in coin form for 1 & 2 "dollar" denominations and paper bills for 5/10/20/50/100.
The "cent" coin was known as the "filler" and came in 1/2/5/10/20/50.
According to Emily Post's guide to manners (a well-known authority on manners in the early 20th century,
"Salesmen and women are usually persons who are both patient and polite, and their customers are most often ladies in fact as well as “by courtesy.” Between those before and those behind the counters, there has sprung up in many instances a relationship of mutual goodwill and friendliness. It is, in fact, only the woman who is afraid that someone may encroach upon her exceedingly insecure dignity, who shows neither courtesy nor consideration to any except those whom she considers it to her advantage to please."
When it comes to shaking hands, Post states the following:
"Gentlemen always shake hands when they are introduced to each other. Ladies rarely do so with gentlemen who are introduced to them; but they usually shake hands with other ladies, if they are standing near together. All people who know each other, unless merely passing by, shake hands when they meet."
At this time, window shopping became much more popular, as women were much more often out in the streets walking. This increased the desire for shop owners to keep their shop windows as neat and beautiful as possible, so as to attract the most number of customers into their shops. So certainly, one of the tasks held by any given shop clerk would be to make sure the shop is always presentable, but particularly from the windows.
Salespersons would also be taking stock of their inventory, as well as keeping track of their sales for the day. Small shops like Maraczek's would have loyal customers, who would often be returning time and again for the same products, and more often than not to the same clerk.