Hello, guys   - I am new in mining and I wanna start with Zcash. I wanna use single GPU to start, and I wanna chose between Radeon RX 480 OR Radeon R9 280 or 290 - I need your advice and ideas.    

Will it be beneficial with single GPU?
And how much H/s I can get with the cards I mention above? (any close idea?)  

thanks