- Making a post or two a day promoting their products/services. [Probably a weekly rate depending on how much creativity you're required to put in]
- Going there probably every Wednesday and Friday to see what they want posted and to take pictures. [charge enough to cover your travel time to work / your personal vehicle expenses, and then add the time spent at the place]
- Going to events or businesses whenever they ask me to take pictures of things they've created for them. [Charge a per event rate, and the prep work and afterwork as well]
What rate makes this work worthwhile for you is a big determining factor right now. Also, refer to this video as you've got the upperhand right now.
https://www.youtube.com/watch?v=D_xmN_w-pq8