Pricing option help for someone who’s never freelanced

Good evening! I’ve been working supply chain jobs and am interested in moving over to marketing in any way I can. So I’ve been learning Canva and Photoshop and have just been creating random pieces of media for fun.

Recently this Art + Music + Entertainment company followed me on Instagram and I DM’d them asking if they’re looking for someone to do their Instagram ads. I went to their most recent event and made 3 sample ads based on the vibes from the night. They ended up really liking my samples and would like to move forward with pricing options. They said they’d want to keep me on a retainer so they can crank out a few ads per event.

I am very new to this. I have no idea how pricing in this industry is done or protocol because I’ve only had a 9-5 set salary. For me, since I have no experience in this field I was just going to ask for $50/ad and maybe 4-5 free tickets per event. Since they’re asking for a retainer, what do you believe is a fair amount to ask?