Mostly thrifted but I have a few pairs of uniqlo chinos for the same reason you stated, that free alteration. I wear black or khaki chinos like 90% of the time, they’re flexible for casual and formal settings so it lets me keep my wardrobe small. Generally all straight cut, with some relaxed or slim fit. I like some room to breathe and don’t want the skinny fit stuff. I also have some dickies and other thicker pants in a similar style for hiking and outdoor work, and some sweatpants for working out. For a long time I had 4 pairs of pants total until I started thrifting. I went to a thrift shop in a college town and got two pairs of brand new pants for $4 each, I love it