I met this chick that was telling me about her last boyfriend who had a penis enlargement surgery where they cut some tendon or some shit like that to make it hang longer. Apparantly his soldier no longer pointed north when erect and what was a bummer for her was that when she rode that thing, there was no "resistance" and it just flopped around. He wasn't able to drive it very well when they did it doggy. She said it was just terrible sex and his dick wasn't that big anyways.
Just spend the $40 if you really need to make your dick bigger. I'm sure your wife (more than anyone else) will understand and probably ask why you didn't do it earlier.