Walmart.com has the Settlers of Catan 5-6 player expansion for $15.69 +tax (with pickup discount). This is a little cheaper then when it hit the front page last weekend. Stock is low at the moment.
https://www.walmart.com/ip/Catan-…n/50016182
Their site is having a little trouble loading (for me at least) but refreshing a couple of times seems to do the trick. Enjoy!