I think it starts at around $15 ish, but it could vary by region. After a successful completion of one session and you get a satisfactory evaluations from students, I think you get a good raise.
I admit it is a good side gig and it might look good on the resume, but I tried to go through this process and it was just too much.
First, you have to apply and then you have to upload a video interview. Then they contact you for an in-person interview.
Then you gotta go through training (paid), and then finally you can start teaching. They pay for planning times for your sessions the first time around. After that, you can just recycle your old notes/lectures to teach.
I honestly think it's too much hassle to land a job that pays $15/hr and doesn't guarantee a full time hours or even close to it.
If it was full time position and guaranteed 40 hr per week, I would have quit my work to do it, but sadly no.
Good luck.