GameFly offers downloads of LEGO: Marvel Super Heroes for Windows for $7.99. Coupon code "MAR20OFF" cuts it to $6.39. That's $4 under last month's mention and the lowest price we've seen. (It's a current price low by $14.)
Note: A Steam account is required for activation.
These tips will leave your ride smelling swell without breaking the bank. Some are also chemical-free.