I use one that came with the table & sewing machine (Kenmore 158.88) when I bought it at a rummage sale. It is a midcentury modern wooden chair with a storage compartment under the seat.
I find it very comfortable and like that it lacks arms. I think I paid about US $85 for all of it (including all attachments & the original instruction book) approx 15-20 years ago.
I peeked at ebay & just the chair is between $79 & $150. Yikes! However, I think they are easily found at yard/garage/rummage sales for much less.