Is there someplace on the web that shows what the promos are for each day?

Weedmaps

They have different specials every day. So best bet is to go in lots of choices.

I got a pamphlet when I was there without really any further information. Sorry I couldn't be more help, I stumbled upon this dispensary by accident.

Yes, weedmaps is the best way to see the daily sales and other information such as strain types offered.