Ebay? For wood? Are you for real? Where do you live, New York City?
Go to any Lowes, Home Depot, builder supply store, lumberyard, etc. They all sell MDF, wood in boards, etc. Some will cut to order, some not. My local lumberyard only sells full-size sheets. Lowes and Homedepot will cut to order. Besides being less expensive than I bet eBay would be, you get to see what you are buying.
"It ain't what you're told, it's what you know." - Granny Weatherwax
Gather the villagers, pitchforks, torches; we march at dusk!
Some days, the supply of available curse words is insufficient to meet my demands.
.....Call me a craftsman, artisan, or artistic, and I will accept that. Call me an artist and you will likely get a quite rude comment in return. I am not a @#$%ing artist.