Ok so here we go my first major fly fishing questions

I have a berkley cherrywood c40 8 recommended line aftma (whats that mean) 6 wt or 7 wt with a shakespeare (ok) free stripping automatic no 1824reel.

The rod is in great shape as is the reel. I understand it is a 6 or 7 wt is the line I should use but wich one should I go with and should it be waight forward or dbl tapered.

should I stick with the automatic reel or get myself a standard one?

also what is a good price to pay for line? one place has them for $30 each but others have them for 60 and up

Also is it good to have both floating and sinking or does the type of flys you plan on useing call for the line?

thanks