You can build your own Rocket, but Groot comes as is. Rocket Racoon will set you back $25.50, while Groot commands $35. It appears you can only order Baby Groot online. The cuddly bit o' wood also speaks, saying (what else?), "I am Groot."
There's also a "GOTG" line of Mega Minis featuring Gamora, Groot, Drax the Destroyer, Rocket Raccoon, and Star-Lord for $10 each. Sorry, no Yondu.