The only standard no-hassle way to get a discount at BN is the $25 annual membership which gives you 10% off in-store or discounted gift cards. Discounted gift cards can be bought from cardpool.com or BN's annual Xmas offer of a $10 gift card valid after Xmas for purchasing a $75 gift card. There was a few days where it was a $50 gift card purchase that got you a $10 gift card. Then there's also the BN credit card for another 5% back.
So, if you just buy $250, you have paid for the membership fee. In the past couple of years, Architecture sets weren't being regularly discounted at retailers like Target/Amazon, etc, so it was an OK discount and any discount is better than no discount..
Now that you can get bigger (20%) discounts regularly from Amazon/Target, it's probably not worth it unless you are also buying non-LEGO things at a B&M store, like maybe books?