I found the cheapest I could at Lowe's. I'd tried going to flooring stores, searching Craigslist, etc, but no one seemed to have anything when I needed it. Even tried to get the last scraps from the large spools at Home Depot, but they didn't have any at the time. I got a 6 x 9 piece for around $20 and then bought the vinyl glue & tool to apply it. It was easy & I'm happy with it so far on my poop board & floor of the coop. (I think it would even be better to have formica on the poop board so it's completely smooth to scrape off the poo!)
I can't see any reason not to use the cheapest, except for it being even cheapER to use whatever you can scrounge up in the way of free/discounted remnants or recyclables.
Honestly, though, having both vinyl and painted plywood floor, I do not personally think the vinyl is all that valuable an addition, assuming you keep a reasonable depth of bedding on the floor, so I would never ever pay *money* for it at all
I found a HUGE roll of brown faux cherry wood vinal at Habitat for Humanity for 12.00! I did my floor and have some left over to give my other chicken friend now.
I've heard that Family Dollar carries boxes of stickem linoleum.. where you just peel the back off and stick it down. Oh, and I didn't glue mine down. I was entirely too impatient and I used small tacking nails all over. If it gets messed up, it's ok. I can just pull it out and redo it. No big.