Oh a snake will do the trick..
We have 4 bathrooms- and last year the most infrequent used one clogged up- it would run but very slow. After trying the plunger rountines etc, he got out the snake and 25 feet down snagged something- pulled it up.. it uh was one of Zubins rubber bones... My husband said a few more feet it would have hit the septic tank and then we would have had a real mess on our hands.
As far as cost- I do not know compared to a plumber, but a snake is one of those things- once paid for it saves all the future service calls etc..