Others can do what they want but I would NEVER pay a beta reader. Never. The only time I would is if that beta reader is also a qualified editor. Otherwise I am not paying some random person money to read my work and give me an opinion. Nope. You can find friends and family that will do that and they can be more brutally honest than anyone. It's just the expertise thing to me. I'm not paying someone who has no technical skills in writing or has no idea what writing consists of to tell me about my story.
Qualified Editor (don't mind paying)
Susie from the block who doesn't know development editing from zippity do-da (nope).
It used to be beta readers were avid readers who were just happy to give input but now they want money. Yeah, time is money but not if your time doesn't have an expertise along with it. Anyone can tell you they liked or didn't like a story but not anyone can point out the technical ways for you to make your story better.
To me it's like if my neighbor asks me if his house is crooked. Okay, sure I can tell him it's crooked but can I tell him why? Can I help him fix it? Heck no because I don't know jack about fixing houses.
I've never seen a point in using beta readers when you're gonna need a qualified editor anyway. I prefer saving time and money and going right to the person who is going to give me the help I need right off the bat.
No disrespect to beta readers. It's cool if writers want to use them but I don't feel they should be getting paid just for an opinion. To me that's like paying random people who review on Amazon.