Reasonably priced, thick curtains?

[Elfina]

I'm searching for some thick curtains for the lounge, in the hope they'll help keep the heat it. The current ones from JL are disappointing, so don't want to spend hundreds...

How about these blackout curtains :
www.homescapesonline.com/curtains/blackout-curtains.html

They seem reasonably priced.
Hope this helps. :)