Actually, I do use any old rags!
I have some linen face cloths, a few old flannels & some cut up old towels in my box of rags for periods.
I only wear them on their own at home, at night or on the last few days when the flow is light. I use tampons at work/out for the first two days when it's heavier, with a smaller cloth to catch any overflow.
They are fine. I soak them in cold water in a bucket in the laundry room, then bung them in a hot bedding/towels wash whenever I put one on.
I find they aren't smelly (no chemicals) & are perfectly comfortable - it's just a piece of folded cloth in my knickers, which is no more annoying than a pad.
I wear fairly fitted pants to hold everything in place.
Cost of periods now = a few poundland packs of tampons twice a year (not in UK & can't readily buy them here).
I've been doing this since using reusable nappies with my dc in my 30s. In fact, old nappy inserts make good pads for overnight.
If I were 20 years younger I'd probably try a mooncup & /or invest in nice washable pads, but in my mid 40s I'm not sure I'd recoup the cost now.