Some pro-built layouts may be "retired" later on -- perhaps the owner or organization wants to "do it over, but bigger and better." A now-used, retired layout might be purchased at a good price, but take-down, transport, and set-up costs would need to be calculated. The actual cost of a soon-to-be-discarded layout might be attractive. You could do some re-imagining with it and make it your own.
TW Trainworx or Dunham Studios may have a "used layout section" in their warehouse. Just saying ...
Mike Mottler LCCA 12394