Trying to curb my shopping addiction via sewing

Hello,

I have recently been getting into sewing to help hit that hunter-gatherer dopamine rush. The problem is, fabric can be EXPENSIVE! I can bulk buy plain colored muslin online for a decent price, but I 1) want more fun patterns and 2) want to try thrifting fabric because buying new cotton fabric is very resource intensive.

I have heard of people up cycling thrifted bed sheets and table covers for their projects, but a concern of mine is fabric type. How do you guys judge the fabric type by touch? I can't do synthetics like polyester and nylon (certain rayons are fine) because in the summer I have a bad time with heat exhaustion.

Short: am having issues balancing my picky fabric choices and thrifting fabrics for my sewing projects. Advice wanted