Used bags/panniers

I still have ye olde canvas panniers from the 90s – they get used once in a while, but their touring days are over (unless I am introducing someone to this and they need/don’t want to buy stuff yet).

You should watch the 2nd-hand market, FB or Craigslist. Or if there is a bike co-op near you, they may have decent gear pass thru on occasion – that’s how I found my waterproof panniers for $40. Or talk to others in your area who bikepack/tour – they probably have a bunch of gear they tried out/still have (like me) before landing on what works for them.