IMo the shade a babe is too expensive-especially if it's only for when he is asleep. I had a multishade expensive too but you could try ebay.
I do think there is a gap in the market for a smaller, cheaper sunshade. Wish for instance that you could get one like a Maclaren raincover, which stretched over the hood and velcroed to the front.
I also used to drape a blanket, a crocheted one so it had small holes in it for draught, was stretchy and dds could see out a bit.