It never hurts to ask, BUT don't be the guy that offers $400 for two pages that total $1075. I politely declined his "offer" first thing this morning
I was thinking more in terms 10 to 15% on a single piece or maybe 20% on the total order of 3 to 4 pieces. Not because I'm trying to low ball anyone either, but I have a budget and want to make a run at some stuff, but don't want to be the insulting guy and get blackballed by my favorite artist or a dealer who might have stuff I want down the line. I'm really not sure about the etiquette
There is another thread in the OA section discussing etiquette and making offers. After much discussion it can be pretty much be summed up with "Common sense and courtesy." If you use liberal amounts of both you can't go wrong.
There is no 'standard' for a proper or fair amount to ask for on a discount. Just go with your gut. If you're in the ballpark of what they will accept chances are they will counter(That's what I would do.) If you are WAY off, they may just decline (also, what I would do.)
Good luck
Thank you Mr.Not so nice. Much appreciated