A Few Ethical Selling Points: Post by Artist Sarah Ross-Thompson
Gallery artist Sarah Ross-Thompson posted this piece recently on her Facebook page - if you're an artist I would highly recommend that you follow Sarah's page she has many useful tips and hints and I would say very much understands both the artist and gallery perspectives in regards to selling.
"I recently received an enquiry, asking my advice about selling artworks via platforms such as e.t.s.y. The enquirer also asked how selling in this way would sit with any gallery representing an artist. Now obviously I can’t answer for a gallery but I CAN share my personal opinion.
It is an interesting point with more and more opportunities for artists to represent themselves via social media, websites and Open Studios. However, having spent over 20 years working with a large number of galleries, I can vouch for the importance of mutual respect. With a healthy regular monthly income from a number of galleries it is clearly important to me to be fair to both them and me. Here are a few points I consider important.
Pricing Parity. If you sell from your website or on an alternative selling platform it is 
best to keep your prices the same across the board. Undercutting your gallery will always be frowned on and may lose you representation. Given the current state of the High Street, commercial art galleries are struggling along with everyone else, so having customers browse in store and then head off to the artist to negotiate a cheaper price is naturally galling to them.
I have a 25 mile rule, trying not to have galleries too close together in an area. Some galleries will ask for exclusivity and in such a situation it is the artist’s job to decide which one will best represent their work. Although this might seem a bit dictatorial...the business sense behind the request is sound. It is easier for a gallery to sell an exclusive product.
When I used to scout for galleries...not something I do much these days now that I have an established track record...I tried to avoid galleries who already had an artist working in a similar way to myself. If they already had an established landscape printmaker then I would be diluting the customer pool for both of us. I know some artists scour the CVs of their competition (nothing wrong with that) but be cautious about treading on too many toes. Absolutely fine if the artist is no longer with a particularly gallery. A good gallery may reject your application for exactly this reason, 
protecting the interests of their existing artist and this will in no way be a reflection of their opinion of your work.
Ultimately there is no ethical code set down when working as a sole trader artist and most of us end up working things out as we go along. Being consistent, reliable, upfront and true to yourself are key. Always have a defensible position. For the few sales I make personally via Social Media, my website or rossthompsonprints.etsy.com I may have some wiggle room for a small discount here and there or the inclusion of postage costs, but the original selling price remains the same as in any of the galleries I work with.