Oil leak question, please help

I was stucked in traffic for about good 30 minutes today, snail pace movement. After the traffic eased a little, about a block of clearing, I noticed smoke was spewing out of my exhaust, I mean a large plume, when I stepped on the gas. It went away after a mile of so of driving.
My guess it that I have an oil leak that's leaking into my manifold if I idle too long at one place?
How much does it cost to fix this?
Do-it-yourself project? Thanks

Blue smoke? Does it smoke on startup (besides on cold days which is usually normal)? Also is it a turbo or an n/a? Does it smoke on decel any? Cost will depend on whats broken obviously, it could be a few things, leaking valve stem seals, bad turbo seals (if it's a turbo), also to clear this up alittle is it burning off of the manifold or out of the tail pipe?