Discounts are available provided you have no debt and are paying for a practice up to midnight on the day of the practice.
You can check you are up to date with payments by checking your club balance here.
You can add as many of these as you like to build up credit for the season. These are then used up as you attend and if you have credit left at the end of the spring practice season (i.e. April next year) you can ask for a refund*.
*Unfortunately we can’t refund the transaction charges, but this would only represent a few pence.