I accept friend requests!
All sales are very negotiable, I usually price based off of comparable horses in sales, but sometimes there are none so I "overprice" and move down from there. Also, if a horse is for sale for passes, I'll be happy to entertain offers in equus and vice versa.
All of my horses are always for sale (well, at least the sellable ones). I'm especially looking to downsize my unis, and am considering selling all my donkey unis.