Straw price varies by season and location, I always watch Craigslist farm and garden section and when I find it for 2 dollars to 2.50 a bale I take my trailer and get 50 bales at a crack, I stack it on pallets next to my chicken run and tarp it. 50 bales lasts me over a year and I usually sell a few bales to friends for garden mulch or their chickens. When I was using wood shavings it was around 4 dollars a bundle, it takes at least 3 bundles, 4 is better, to cover my coop after cleaning and another bundle every week or 2 to keep it decent. If you have to pay 4 or 5 bucks for straw then wood may be cheaper, I refuse to pay that much that's why I buy in bulk when I find a deal. If I had a building to store it in I'd get hundreds at a time when I found it for 2 bucks and sell it on Craigslist for 3 or 4 bucks like everyone else does but I don't have that kind of storage lol.