If you want grass hay bales proper, it can be had. The racehorse people want it and are willing to pay dearly for it. If your supplier doesn’t carry, then try calling the feed store that covers Santa Anita (since IIRC you are in southern CA?) and I’m sure they have some, though at $20+ a bale for sure.
My grass hay is grown across the street so is pretty affordable. Feed stores in my area usually buy grass hay from Oregon, so there’s the shipping cost, but at least fuel prices are low now.