Discount Codes or Secret Tiers

I want to be able to give incentives for patrons to sign up for my Campaign. There’s the “special offers” feature, but it only lets me add a one-time Benefit.

A discount code that can be applied to temporarily reduce the price of a tier would be welcome. For example, in the first 3 months you pledge, you get 20% off, and after 3 months, you get bumped to the normal price.

Another idea would be adding “secret” tiers. For example, I can distribute a special code to prospective patrons, and when they put it in, they see tiers with different prices.