The Eeveelution cape can only be purchased in the online exclusive bundle, which you can pre-order on the BAB website. It includes a pre-made Eevee, a 5-in-1 sound clip, both outfits and the promo card. It costs $62.
The basic Eevee plush is $28. The pajamas are $12. Eevee will be available in stores on September 1st, 2016.