There are a lot of sellers on Etsy that sell leather suspenders for between 40 and 80 dollars.

There are many boutique sellers of various prices and material but I have no frame of reference in terms of quality. From a quick google search: Sellers like Col. Littleton

Bykowski

Grommet's leathercraft

Herd Wear claim to be based in Pennsylvania and that their bison leather suspenders are made by an Amish family but again I have no idea about quality or if any of it is true.

https://herdwear.net/collections/belts-and-suspenders/products/bison-leather-suspenders

I concur with another commenter in looking for stores that cater to Amish or Mennonites or just stores that sell "western" or "rural" attire in general.