I am asking this question on behalf of a model, we did a TFP photoshoot together, and she has found an online magazine/website (similar to a lad mag website, think FHM - its not FHM!)

Anyway, they liked the photos and asked what would be our price for them having exclusive first publishing rights.

There are 20 photos in this collection,

From what I can tell, the main revenue stream for this entity is ads, one of their FB pages alone has over 100,000 likes, so they have quite a following..

But I have no idea (sort of suggesting.. well, how much are you willing to pay?) to suggest as a price?

There is no online mag ie (magcloud) just website articles, so its hard to even suggest a percentage of sales in this instance too..

I don't want to come in too high, and I dont want to undervalue our product either.

Any suggestions on how I can figure out a fair price tag?

I would consider what you could earn elsewhere from the photos. Do you expect offers from others?

Look up a stock agency rate, and then decide what is fair to you.

Can you contact someone who has already been published in the same magazine?