Hi Harbey
Back when I was in the art gallery business, their was no discounting of art work. If an artist or an art agent caught you discounting art work, they would not sell to you again. People buy art as an investment and if a gallery discounts, it makes all of that artists work go down in value. Believe me other galleries watch what you do and will report you in a split second. If this is a reputable gallery, I don't see much chance for a discount. I was in the business for almost 40 years and have never given a discount on art work.
Regards,
Bill Parrie