iRewardHealth - Motivating healthy behavior change
Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.
Tep - Fitness tracker meets tamagotchi. Don't starve it!
Fetchee - Fetchee is a free price tracking wish list app that works with all online stores worldwide.
Physio Health - Stay healthy, get rewards.
Keepa - Price history charts and the option to be alerted on price drops for all Amazon sites.