Where can I get cheap yoga pants?

So, I'm starting to take up yoga and I would like to own at least one pair of cotton yoga pants. I've been looking online and everything I've found is always too pricey. I think the cheapest I've found was looking at the fleece pants at walmart. I feel like an idiot, but, does fleece breathe like cotton would? That's all I'm finding at walmart and if I cannot find anything cotton online, then, I'll probably just go back to Walmart. Any suggestions would be great.