How Long Is A Piece Of String?

Has anyone a definitive word count for each type of piece?

A Nice Cup of Tea and a sit down.

Is a novel of a minimum length? Are there any actual rules about this? I found myself looking at word counts in relation to value for money when I'm buying an eBook.  For my own work I came up with the ideal solution; every 33,000 words roughly will cost $1. From observation that is a fair price. I think that the reader doesn't want to pay alot for a shorter less meaty read, when there is another book for the same price for triple the word count.
My main gripe is NOT that shorter books are offered online... far from it. I just read a great Novella by Brandon Sanderson and really enjoyed it. But that is the key, it was called a NOVELLA. It didn't pretend to be a novel, which I understand to be a book of 60,000 words or above. So I was a happy customer, the description matched the content. Of course I want to buy a book that is well written, exciting, intriguing and enjoyable; but the feeling that I might run out of string is not pleasant. Normally I like long books! I love to get my teeth into something when I have the time.... that is the thing at the moment. The piece of string has to be the length to suit the reader and their reading habits, personal preferences, and tastes in fiction.
But just as I like to get a big vat of strawberries and guzzle them to my hearts content, I don't want to find out I could have got a better, juicer... and larger punnet from the stall next door.
I think it makes sense to not try to get away with describing your short story/novella as a novel, when it plainly isn't. I came across this recently, and having clicked onto the page of a writer whose "novels" were on display, was disappointed to find perilously low word counts. I felt offended because I write past the 100,000 word line every time. My next two novels will be both a good read.
Anyway.... food for thought. I ask that you sell your wares fairly, describe them accurately, and don't hike your prices through the roof! And if you are a savvy reader you'll already know what you would see as a bargain, and what IS good value. So let us reckon on our potential readers and future fans being given a good deal.

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Enjoy!