Mystery Pokébag (5 for $20)

What better way to start your Team for Battle then to have a bag full to have it prepared - even if it is a surprise which team you are getting.

5 for $20 - and any of the Poké related items that state "Part of creating your Pokéteam. (Part of Pokébag)" in the description may be one possible options you may receive. 

Pokémon are being added and when they run out, another will replace (or be refilled).