you could try going via waste aware scotland -
http://www.wasteawarescotland.org.uk/html/compost.aspclick on the link to "buy a compost bin"
enter your post code and it should give you a list of the bins in your area
you'll need to go through the purchase process a few steps to get the price though
- but you can always cancel instead of confirm!!!
alternatively, do you know anyone in falkirk council area??