AT&T is currently having a promotion where if you buy 3 accessories you can get 30% off anything lower than 100 or 10% off anything greater than 100.
They are also only selling Google Nest Audio for 79.99 before promo. If you need only 1 or 2 Google Nest Audio you can add an accessory for $5.
For cheap items just sort from low to high. There are a variety for $5. They are phone specific though. The only one that isn't is the touchless key.
So it works out to
3+ Google Nest Audio: 55.99 each
2x Google Nest Audio: 58.49 each
1x Google Nest Audio: 65.99 each.
YMMV: Check your credit card for an offer for $35 cashback after 2 purchases of $17.50 at AT&T. You will have to split the order and buy more filler items though.