My rewards have been varied and intermittent. This is for two reasons. 1) I'm not the most organized person, so timing a reward to match specific milestones is a bit difficult for me. 2) As a behaviorist, I believe that random/ intermittent reinforcement is the most effective.
That all being said, here are some things I have indulged in with the idea that smoking would have prevented these either physically or financially: more dinners out, a gym membership (something I had been wanting for a while, but didn't feel I had the money for until I quit smoking), an upgrade in to my phone/ phone service (internet and apps gave me something to do with my hands instead of smoking), longer and more frequent bike rides than I used to take (since I'm in better aerobic condition now), and a couple of pairs of toe shoes that have made my sore feet feel so much better
I am contemplating a big reward around the time I reach the one year mark. I have always disliked my physical shape, as I have skinny legs and butt with a thick waistline. Even when I'm in very good condition, I'm still disproportionately thick in the middle. For me, it's genetic, but, according to my research, it was also aggravated by my smoking. So I was thinking of going to get Coolsculpting, a procedure to freeze fat cell in specific areas--usually used for belly fat or thigh saddlebags. Supposedly, the fat cells will gradually die off and leave the body in 2-4 months after the procedure. The cost of the procedure is about the same as I would have spent on cigarettes for a year. I'm still not sure if I'm going to do it, but it's a thought.
I used one every day like a carrot on the end of the stick. For me, that carrot was a beautiful tasting beer at the end of the day if I was a good boy and didn't smoke! It worked then and is still working to this very day! 
