How to get enough protein when you’re broke?

I’m a single mom that’s been kinda going through it financially lately. I still have a goal to lose weight. Honestly the gym is where I can just forget about things. But I’m looking for cheap sources of protein. I know I can get chicken pretty cheap when it’s on sale. But the amount of protein is where I’m kinda struggling. I’ve been told to aim for like 130g based on my goals. Does anyone have any ideas?