I called Wayfair to find out if hosts are eligible for their Business program and it turns out they are! From what I have seen so far the discount varies from item to item, but there are also volume discounts (which could be great if you have a large place like us or manage multiple properties). They also say that you have a personal account manager which in my experience just means annoying phone calls but I guess it could come in handy if I decide to buy everything for our place with it.
I believe you can just sign up online. There is also a referral thing to get $50 off your first order if you want to message me (we would also get $50 credit and I don't want to come off as trying to plug this for my own benifit so if there is an easier way I say go for it :D).