https://www.theverge.com/circuitbreaker/2018/7/23/17602418/microsoft-surface-go-costco-mid-range-bundle-specs

The Surface Go was originally announced in two variants: a $399 budget model with 4GB of RAM and 64GB of storage and a $549 model that doubled those numbers to 8GB of RAM and a 128GB SSD. But, as spotted by Neowin, it seems Costco is selling a previously unannounced midrange option: a $549 bundle that offers a Surface Go with 4GB of RAM, a 128GB SSD, and a Surface Type Cover (which normally costs $99).

Although the configuration is odd, the pricing does seem logical. $549 for the listed bundle would be $50 too much if it was really the base model, and it would be underpriced $100 if the listing was meant to be the top-of-the-line model.