Help Pricing Licencing

Dropped in at the deep end

I have been dropped in the deep end and was recommended by someone to ask here for help.
My predicament is that I created a typeface/font a while ago and wacked it on dafont for free for personal use and left a note saying email me about commercial use not expecting anything. I have now received an email from an award winning ad agency asking for a quote for 15 users, print and web use. This is pretty great news to come out of the blue but I am really stuck on how I'd price this. It's just a singe weight font with a small amount of glyphs(bare essentials). I also would love help on how I'd find create an appropriate licence for this.

I really need help from someone with a lot more experience than me and this seems to be the place to be.

Thanks in advance,