I slept in a £14 bag from Millets for a couple of months bike touring last summer. It was perfect and I loved it. However it was a one season bag for the summer so you wouldn't really expect it to be that expensive or warm, pretty much a sheet folded in half with a zip.
I also hadn't put in nearly as much consideration as you, I thought a sleeping was a sleeping bag, some were thick and some were thin and I chose accordingly.
I slept in a £14 bag from Millets for a couple of months bike touring last summer. It was perfect and I loved it. However it was a one season bag for the summer so you wouldn't really expect it to be that expensive or warm, pretty much a sheet folded in half with a zip.
I also hadn't put in nearly as much consideration as you, I thought a sleeping was a sleeping bag, some were thick and some were thin and I chose accordingly.