So I know someone who wants to sell me this camera:

He said he'll give it to me for 300. Think its a good deal? I currently own a MF camera so I dont have a clue about how these things work.
Does it come with pretty much everything I need? (It says it includes one 4x5 film holder). And how do you focus with these beasts, it's not like a rangefinder is it?
It comes with a 210mm, which isnt wide enough for me. So i would be buying a 90mm when I get the chance. What is lens compatibility like? Price range?

Thanks guys!