I have a pair of heavy weight Bellwether cycling pants that I found at a yard sale a while back for 50c (!!!!). They are a little big for me but they are very warm. For 50c I'll make them work. In the coldest weather I wear a base layer underneath them. Today was the warmest morning yet 40F, so I left the Bellwethers home and rode with a base layer and Hind running tights.

My SO also has a pair of these same Bellwether tights. His are in better condition than mine and fit him well. He got them at a gear swap for $2. He loves them.

Just did a web search to see if these tights are still out there - they are, and cost ~$70!