Evidently these are the best tumblers and hard to find in stock at a lot of stores. The reviews are excellent. Regular price most everywhere online, if even in stock, is between 34.99 - 39.99.
I went to this site below and got a pop-up to put in my email for a 20% off code for my first order. I did and used it with the Yeti tumbler + free shipping (limited time) and no tax for a total of 27.99. Yeti does not allow discount codes for their products so a discount is hard to find.
I'm sure you could get the 20% discount on other items with free shipping as well.