Savings challenges, with the dates filled in.
Pick a target and a start date. You get every contribution with its own date, a tracker you can print, and nothing to sign up for.
Money Saving Challenge
Pick a target and a start date, get every contribution with its own date, and print the tracker.
Why these have dates on them.
Most savings challenges are a grid of numbers. You fill in a square, lose a week, and the grid has no idea — it says the same thing in week seven that it said in week one.
These generate a real schedule instead: specific amounts on specific days, worked out from the target and the date you gave them. Print it, or keep it and get a reminder before each one is due.
The arithmetic is free and always will be. The part worth paying for is what happens the week you miss one.