Came across this while searching for any discounts for the Sonos Arc. It appears that they have discounts on the full range - I've listed some of the more commonly searched items below:
One SL $249
Gen 3 sub $899
I haven't ordered from them before so can't comment on the service, but prices look good.
Website also says free delivery, but I couldn't see if there was a min spend. That said I assume Sonos products as they're not the cheapest would likely qualify!