Luminosity is the brain training program for Android. The full service experience requires annual subscription of Lumosity. Everyone do not get the service at same price. The price changes time to time and they often offer a discount on some special occasion, like Black Friday or New Year.
If you want to get Lumosity at lowest price possible, then use the power of bargaining. Go to subscription page, follow the steps, and change your mind at the last minute, and wait. Sooner or later they will come up with a discount regardless of the time of the year. The discount will only be applicable to you. You may get up to 35% discount.
The best thing is that, once you get a discount, the subscription price gets locked as long as you keep your Lumosity subscription.