This article is a stub! We are blushing super hard, but before putting this here there was just no Toggl help page at all, which was even more embarrassing.
Ok, but the very rough story is that you pick any subset of projects, tags, or clients (or just count all Toggl-tracked time) when you create a Toggl-fed goal on Beeminder. You also choose how many hours per week you want to commit to, and whether to start with some initial safety buffer. Then just use Toggl like always and Beeminder will automatically plot your cumulative time spent on a fancy graph with a Yellow Brick Road denoting the rate you’ve committed to. Keep all your datapoints on or above that yellow brick road or get charged real money. It’s very motivating!