So much in this thread is just plain wrong.
The cheapest signed and authentic Warhol prints are around £5k, these are usually obscure subject matter and images with serious condition issues or parts of broken up portfolios like the flash series. There is a very small lithograph published by the UN which is signed from an edition of 1000 which is around £3k. His most popular images like the Soup Cans, Marilyns, signed Cows, Electric Chairs, Maos, Flowers etc start around £15k (usually with condition issues) all the way up to around £300k for an edition. The vast majority of signed ephemera is fake and or impossible to authenticate as are prints outside the edition and the volume of fakes in the Warhol market is huge so tread carefully. Always spend time checking provenance and try and buy from a reputable source where you have recourse if there is an issue.

Some of the prints were authenticated after publication by the now defunct Warhol Foundation (Authentication body), these carry a stamp and unique code and this of course adds value, but the absence of a stamp does not mean the piece is not authentic and given the body no longer exists a stamp and code does not mean the piece is 100% authentic.
The disparity in values is wide between editions because Warhol produced so much and covered such a broad range of images and subject matter. The same factors effect the value of his work as any other piece of art, subject matter, provenance, condition, colours, edition size, history, trends etc, but obviously given the breadth and volume of work there is a big spread of values.

The Sunday B Morning black stamps are not official Warhol prints, they are named in his catalogue raisonne as being unauthorised. I’m not going to get into the full story but it’s on the internet. He did sign a few of these as a kind of protest writing this is not by me. These are extremely rare and harder to find than the Factory editions, if you’re offered one in all likelihood it’s fake. Any image other than the Marilyns carrying a black stamp (Maos/soup cans) is fake and produced by another outfit later on after the original Sunday B Morning Marilyns. Sunday B Morning is now based in the US and uses blue stamps, they use the same colour codes and techniques as the factory editions but not the same screens as many people claim. Despite their low value people do sell fake Sunday B Morning blue stamps so buy direct from them if you want one. They are good replicas for the money but aren’t investment pieces.

As for Warhol’s market going forward my crystal ball is on the blink but if performance from the mid 90’s to date is any indicator of future performance you’ll struggle to find an artist with better investment credentials.

Is Bleca mecca on eBay the seller by any chance? if So avoid it's fake, well avoid it anyway because it's fake but doubly so if sold by that charlatan.

Thank you for your feedback, can you please let me know why you're 100% sure is a fake?

This is without question a second selling account for Blecca Mecca, thanks for pointing it out, he's a notorious forger based in Sweden.

This is pretty sad. I'll get the ball rolling.

This is quite an interesting read. Post from November 2002. Below is from the former owner of SBM:

The content of the reply went as follows:

I am a piece of a legacy of Sunday B. Morning. I worked together with some of the original men that started with Sunday B. Morning.
These men were friends of Andy Warhol. I saw tons of photographs of them together with Andy. One died some few years ago, and I started working with his brother who still had an existing stock of prints. This stock is long time ago sold out, unfortunately.
One of the founders of Sunday B. Morning was the Belgian MR. Van
De Plas (has past away in the late eighties).
He was also the one that invited Andy Warhol to Belgium to meet Hergé (father of the comic strip Tintin) and Paul Delvaux in the eighties.
The name Sunday B. Morning is still a mistery : I have heard many things from some of the original crew…”On a Sunday Belgian Morning”…”Sunday Bloody Morning”…nobody could ever give me the right answer.

The prints now sold are not made with the original screens. These are still existing in a secret place, not being used for the moment, in a central European country, well know for its banks.
No prints being offered on the market (except the old original Sunday B. morning prints) have been printed recently on these screens. I can assure you that!!
Now they are again being printed, everything OK with rights and so on.
In the catalogue Raisonnée they are speaking about the original prints
with the black stamps. We are now using Blue stamps to show the difference, we don’t want sell recent prints as old ones and lie to the customers. We don’t want to pretend these are the original ones. We have to be honest with our customers.
I can assure you that most of the men on the net presenting the prints, have
bought them from us (My friend and I).
Somethimes there are prints being offered that are not worth the paper they
are being printed on. I saw everything on the market, about 4-5 different fake editions I know.

Full article: www.mistersnappy.co.uk/?p=73

Thanks for the heads up – I gotta go!

Can you provide is with a range of what you are hoping to get or an expectation/starting point for offers?

Excuse my ignorance., stamped but not signed original?

Yes got it from Christie’s around three years ago.

Hey let’s talk via DM please send me an offer there thanks.

eBay is the next website over...

Some info on this series
revolverwarholgallery.com/portfolio/muratti-ambassador-cigarettes/

How much do these go for? Can't you get the Dracula Signed Print for around 20k still if looking?