I sell this way sometimes, I'd call it consignment.
I think best thing is just to be frank with them and ask them what there mark up is. Some shops will ask you to set the price, and when it's sold they'll take a %, you need to ask them what % they take.
Other shops, ask you what you want for it, and they if they sell it, they'll charge whatever they like (or whatever they can get for it) and once a sale is made you'll get your price - if that makes sense.
When it's been an shop I was unsure of, I've asked them to pay wholesale price upfront for a few items, as a gesture of good faith sort of thing. You don't want to be just filling their shelves for free. But at the same time, they wouldnt' have asked you if they didn't think they could sell your work.
Perhaps tell them, yes great, lets do a 6 month trial, and if it doesn't work you can get your stock back. If it is working, all the better.
Hope that helps
Also, make sure you get a contract.