The SAT is probably the most attainable piece of the application process for a poor kid to succeed at. You literally just need a guide book or two and enough time to study. One good smart friend helps if you're lucky enough to have one. Literally the lowest barrier to entry for a kid stuck in a shitty school with parents that aren't around and no money to your name. Is it still a hurdle for poor kids? Undoubtedly, but I can't think of anything that can show academic capacity that requires fewer resources.
Dead Comment
As one option, look into professional house-sitting (common in US, not sure elsewhere). Essentially, people with high end homes, who are going to be away for a period, who want someone they can trust not to wreck the place to just be there.
But essentially, just live somewhere else for a minute. For me it takes about 5 days to start living instead of visiting.
After my mother's cancer diagnosis, when treatment was in progress but surgery still scheduled some time away, and I had a job I hated, with co-workers whose morals I didn't share... I spent a few weeks in Japan and Thailand. (Mostly paid by reward points, long saved)
It was amazing how refreshing my view on my own life was, from a different vantage point.
When I got back, I quit the job, took some time off with the aid of savings, and spent time with my mom through her treatment. I'm not sure I would have realized that was the right path without the distance. (And it finally resulted in one of the best jobs of my career)
[1]: https://www.youtube.com/watch?v=NVGuFdX5guE