GoHastings via eBay offers Rick And Morty: Season 1 on Blu-ray for $10.25 plus $2.98 for shipping.
That's the lowest total price we could find by $3, outside of the mention below. It includes 11 episodes.
A close price: Amazon
sells it for $14.99 with free shipping for Prime members. Update:
: Note that it's temporarily out of stock, however you can order it at this price for delivery when available.