Whether there are buses going preferably from Huangdao or from Qingdao to Shanghai, and vice versa

If so, want to know their current ticket prices; and also, whether tickets are supposed to be booked in advance (somehow?) or can be purchased at anytime at the bus stations as well (even right) before the departure date (and time) (I will need return tickets, and looking for the cheapest possible solution, since I find train tickets too expensive for 2 persons..)
Thank you in advance for your kind reply!
Kind regards,
Andrea