Offline affiliate programs that will work for print publications

What major affiliate programs are constructed so that they will also work offline, specifically in a print publication?



Background:
I am about to do a print publication that is a crossover between online and print (multiple crossreferences in the print material).

I will produce some ads in this publication myself, similar to the online affiliate system.

The problem with print is that there is no way to track a click or a sale with traditional link or cookie.

One system that will work is with codes or cupons.

For example iHerb com has a system where all new users get USD 5 credit by entering the affiliate code of the referer. The custumer therefore has a strong incentive to enter the affiliate code that will be tracking.
This way I can make an ad in the publication myself and print my iHerb code for readers/customers to use. This can for example be done as a coupon.

An ad for a custom Amazon store, go to... "astore" astore amazon com will also work, but not quite as well as iHerb (as there is no incentive as such to enter the code).

We need more creative ideas.
I am also pretty sure this is a field where there are opportunities (I have searched for solutions but not found much.)

Is there a general name for such programs as iHerb? Where the customer gets something for entering a cupon code with affiliate tracking?

Thanks