Filemaker typically discontinues selling previous versions very soon after a new version release.
Upgrades are offered for a limited time after a new release for the more recent FMP versions.
Currently ver 12 offers an Upgrade for $180
If you have FileMaker Pro 11, 10 or 9, you are eligible for upgrade pricing on FileMaker Pro 12. Please review details below before purchasing.
If you have
You are eligible to
FileMaker Pro 11 Purchase upgrade version. FileMaker Pro 10 Purchase upgrade version. FileMaker Pro 9 Purchase upgrade version - ends September 27, 2012. FileMaker Pro 8.5 or earlier Purchase full version.
Finding a license or FMP on ebay or such is not very easy (did the search many times).
Last I heard, FileMaker still offers a 'downgrade' option to purchase Filemaker 11.