A few weeks ago someone on this board mentioned substituting a wool horse pad. A 30" x 30" wool pad is $26.68. I haven't tried this, but I saved the website they mentioned:
https://www.statelinetack.com/item/mustang-square-wool-pad-liner/SLT901243/?srccode=PJSLT&utm_source=affiliate&utm_medium=referral/&source=pepperjam&publisherId=43737&clickId=2658579345