Pricing for Photo Compositing

Hi, I’m wondering if anyone can advise. I’m taking the computer graphics course now, and as soon as my family members heard that I know graphics they are all asking me to do photoshop work for them. Mostly I’ve been asked to do photo compositing (Basically like what a photographer would be doing). One family member wanted a headswap and that I should blur and touch up the photo to make it look professional (wasn’t very difficult). Another wanted me to do a more complex composite where I combined two people from two different photos onto a third background and then I had to make it all match up (was lots of work, and lots of back and forth). I am charging because I don’t want to be taken advantage of but I have no idea what to charge! Can anybody offer advice? Any guidance would be appreciated!