Hi. I came up with an idea & was hoping someone can tell me if it's original, and if so, how do you go about selling it? I know there's lots of effects similar but perhaps not exactly the same.

The effect - After finishing some card tricks you realise you have one more effect to show. You place an envelope in full view & hand a spec the deck. They are asked to put the deck behind their back & turn over any card they want. They hand back the deck & you fan through until you find the face up card. It matches the prediction in the envelope! The face up card is removed from the deck. It has a different coloured back to the others! And the final kicker, the deck is turned over to reveal all other cards are blank!

Any comments most welcome

It sounds somewhat similar to Eric Ross's "Election", at least in methodology. But yours uses a single deck, and a blank deck as a kicker. His has two decks, two spectators do the action behind the back, and both pull out the same card, only each is a different colored back from the deck they are holding.

I'm thinking about a trick myself, something with red and blue backs and a reversed card. I have the same problem: where can I put it for sale?

Maybe someone can create a site where people can offer their tricks. The people offering may not be bigsellers or professional inventors, but small time tricksters and amateurs.

Like eBay, but not as an auction, but as a virtual mall with small shops in it.

Hmmm, that does sound quite similar. My version does only use the one deck with the added bonus that the spec believes the cards have faces to start with. Not sure if 'Election' does that as I don't have it.

This is only tangentially related, but I wanted to share it with someone:
Put a blank facer on the face of the deck and do a thumb fan in the right hand. Your deck now appears to be blank.