That's pretty much the best price you will find for a twin pack. You can buy a 60 pack for around $39 HERE if you are willing to buy that much film at a time. If you don't want to wait for the film to arrive in the mail, Best Buy usually sells twin packs for $14 plus tax, but they tend to run out quick at the Best Buy near me. All in all, it will usually be around $0.60 - $1 per picture with this type of film.

I just checked on Amazon the the one I usually buy is a little more expensive than usual: https://www.amazon.com/Fujifilm-Instax-Mini-Instant-Value/dp/B01E3QM34W/ref=mp_s_a_1_5?keywords=instax+mini+film+bulk&qid=1577417790&sr=8-5

Just keep looking out for a good sale on it!