You could try finding a lab you think you're interested in and emailing to ask if you could shadow their research assistants for a couple days and attend a couple lab meetings. During that time, evaluate the day to day work of the RAs. Is that what you're looking for? Does that match your goals for the experience in terms of the money, skills, and opportunities etc that you're looking for? Are the RAs given opportunities, or are they treated like permanent worker bees?
Most importantly, evaluate the character of the PI. Is the PI reasonably kind to the RAs? Offer mentoring, training, opportunities, etc to the RAs? How does the PI react when somebody makes a mistake?
Someone working for a tyrannical PI once told me to pick the lab based on the PI, not the research they're working on. If you care about the research, maybe try to pick the lab based on both.
If you like what you see, ask if you can volunteer. If what you really want is a job, ask the PI beforehand if they might need a new RA within the next X months. After some months, they might hire you.
If you don't like what you see, move on and restart process with new lab.
Alternatively, you could always just find a job that doesn't unofficially require pledging (I.e. volunteering).