@Jaclyn67 What you want for an Airbnb are decent quality, but not over the top. No need for 1000 thread count sheets unless you have some super luxurious, expensive listing.
Sheets are something you'll have to replace on a regular basis- most stains can be removed (hosts become laundry stain experts) but some can't.
I've found decent sheets online from various places and at the kind of stores that carry discounted brand name stuff because it's last season's or has some small flaw or a store went out of business. There's a chain in Canada called Winners where I've found good deals- I don't know what the equivalent would be in the US.
I've even gotten quite decent sheets at Walmart.
While you will likely start out with "sets", it's a good idea to decide on a color scheme so you can simply replace a fitted or flat sheet if one gets ruined, rather than have to buy another whole set. So that could mean going with all white, or say shades of grey or blue or whatever you like. Then you could use a dark grey fitted sheet, a light grey top sheet and medium grey pillowcases if need be, or even a grey patterned sheet, and it will still look purposeful rather than a hodge podge of whatever you happened to have clean.
My listing is eclectic and colorful, so I even use a totally different color fitted sheet and top sheet sometimes- like a burgundy fitted sheet, a grey top sheet, and pillowcases I make myself from patterned quilting cotton that has both colors in it.
I've bought colored towels at Walmart, and a lot of hosts I know swear by those 10 pack white towels from Costco.