Next premium purchase?

It is going to be hard to predict what hey will do in the future. For the first black friday sale, many of the premium characters were on "sale", but in last year's sale, there weren't nearly as many. Outside of the black friday sales, there's been a few smaller item sales (back to school, octoberfest) and sales in events (barney in the space event and miss springfield in the casino event), but there's no pattern to them.

If you insist on waiting on getting jasper, I think there's a good chance he will eventually go on sale, but it might be years before that happens. If you think you'd want him, you should think about how long you'd be willing to wait.