Paid critiques can be great but either way, I highly recommend you either get into a small critique group or find one or two partners to exchange with. Multiple people exchanging together is generally better because then you can see what other people think about manuscripts that aren't your own. That can be eye-opening. In addition, when YOU critique someone else's work (especially frequently), that tremendously improves your own revision skills.
There are lots of people who have day jobs in addition to writing, btw.
Finally, it is extremely common for new writers to feel paranoid about sharing work. I felt the same way when I started out (around 2007). I was worried about someone stealing my ideas. But honestly? You kind of have to get over it. I've seen people in my critique group write about the exact same concepts and the end products still come out totally differently. That's because it's all about your unique voice and execution.
Long story short, if you pay for a critique, I'm sure you'll find it very useful. I'm not discouraging that. But a critique group will benefit you more in the long-term.