Just confirming the “too expensive” comment. Can you take the seats out? (Check underneath.) It could be a DIY with some inexpensive fabric, foam, and staple gun. Almost any plain fabric would be an improvement over the current fabric. They are beautiful chairs! You could also search for photos for those little chair covers, some with ruffles; some with pleats; some plain that extend over the seat edges and tie in the back.

If the cushions are still cushiony, then, DIY upholstery is pretty easy. The upholstery is often just stapled underneath the chair. You need cheap upholstery fabric, which you find on-line or in the bargain bin of places like Joann.