We got this mat off of Amazon for a reasonable price. It's nice and perfectly sized.

https://www.amazon.com/gp/product/B07QXLZNN9/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

I saved my money and bought one on Amazon. The following 2.5’x5’ worked perfectly:

Balance From Go Fit High Density... https://www.amazon.com/dp/B07QXLZNN9?ref=ppx_pop_mob_ap_share

I have no relationship to the manufacturer, not an affiliate link.