What kind of arrangement do artists have with the galleries that show their work?

Actually there are several types of galleries and each operates differently:

Frame Shop Gallery: Often will do the framing/matting. This gallery will agree on a price for the artwork- the artist is entitled to half that amount (some galleries take more and some less)
Then the art is priced at the agreed price PLUS the cost of the framing. When the art sells the frame shop keeps all but the agreed on percentage of the art alone.
Example: Painting agreed price $1000.00 Is listed for $1400 (added $400 for framing) painting sells and artist gets $500.

Another is a co-op gallery. This is a group of artists that pays to exhibit and show work in a building. Each artist pays a fee to belong and a percentage of any sales. The artist frames and mats the art themselves.

Vanity Galleries are to be avoided. They prey on artists wanting to say they had a “show” to put on their resume. These galleries charge huge fees and hold a lavish opening party. Often all promotion of the event falls to the artist. Such galleries are well known in the art world because they do not base artist selection on talent so much as the willingness to pay.

There are other variations on these galleries. Some require portfolio approval and some will pick and choose what is hung. Some require that the artist do promotion and pay for an opening while others will cover the cost.

I had my paintings in a local gallery for a time. They helped me with the matting, I set the prices with them and it would have been a 60/40% split if any had sold.

Each gallery will have their own arrangements. Some will offer matting and framing services, but you will want to find whether that would work for you. Talk to a few gallery owners and find out what their requirements and arrangements are.

Usually a commission, and artists pay their own installation costs for exhibitions. Some artists, who have a certain recognized market value, may go on a yearly salary in exchange for producing a set number of works for the gallery during that year.

A 20% commission to the gallery is pretty standard, but varies. Just remember, everything is negotiable. If they tell you otherwise, they are probably not confident they can sell your work and you are better off somewhere else. Also, make sure your work is insured while in their hands and get receipts, not just for sales, but for anything you leave with them.

I think sometimes they have to pay a percentage of the sales price of the item, and at other times its a flat fee.