All you really need is a little plastic thing of needles ($1), some pins ($1), thread (varies but even good cotton thread isn’t that much), scissors (where you might actually consider investing a little - do not use these scissors for anything else, and consider a rotary cutter if you really get into it), and fabric.
Fabric might seem like the pricey part of the equation, but consider how much a thrift store is going to charge you for a duvet or a pile of t-shirts! I have something like 30 t-shirts I spent maybe $5 on several months ago, and I’ve been working through that pile for a while.
You can turn a t-shirt into a pillow, a reusable bag, use the scraps to patch clothing, make dolls, quilts… The bits that get to be so small to be unusable for a scrap quilt you can use to stuff things.
It takes a lot of time compared to machine sewing, but it’s an activity that can be done while watching a tv show.
Counterpoint: hand-sewing reduces your impact on the environment more because you can’t impact environment that much with both hands occupied for dozens of hours. It’s like touching grass but productive.
By that logic, the best thing to do for the environment is to die - which is probably true, it’s just not a very good (or even particularly interesting) argument.
right on both counts
You can take your stuff outside and sew and touch grass at the same time.