I have the lightest pair of scentlock overalls i could find. No matter the season i dress as needed then throw those on top. They were just under $100 on sale from cabelas.
I am not sure they work all that well. I would likely just buy regular overalls of the cheepest variety if i had it to do over.
As far as scent, the smartest hunter I know just wears a cheap undershirt for a weekend working outside then ties it to his deer stand. The deer get used to it before season starts.