I bought a 1936-S dime from the local coin shop. It appears to be in near perfect condition to my untrained eye, but the cardboard holder reads "VF/XF". This excellent dime was around the same price as many dimes of the same design that were in much worse shape. Did they make 100 trillion 1936-S dimes or is there some other reason that I got this treasure for the price I did? ($3.25)?
The actual number of 36S Mercs was 9,210,000, according to Red Book. Without a picture to see both sides clearly, it would be hard to give an opinion on why you picked it for $3.25. Price from numismedia.com for VF/XF is $4/$5. There may be a reason why the dealer priced it at what you paid for it, like maybe a noticeable cleaning, perhaps there's some type of damage to it that you're not seeing. Post some pics for us.
It was the lowest mintage that year, as the P/D are 87,500,00/16,132,000. I'd agree that it is a common date and mint.
It sounds like you purchased an inexpensive, circulated, common Mercury dime for a reasonable amount that neither buried you nor made the shop owner wealthy.
It's a great coin and looks uncirculated to the untrained eye. I might not have gotten a spectacular deal, but it was worth it to me.