What's VMWare Fusion upgrade policy? I consider buying it, but a new version will probably come out in September alongside OS X 10.11. Will I get a free upgrade, or do I wait until September?
You need to contact the Sales department for VMWare, and come to an agreement with them.
Last year, I had bought Parallels a few weeks before a new version release, but (without my prompting) they simply tossed me an e-mail with authorization to install the newer version.
In general, a Sales department is sensitive to avoiding the impression that they're double-dipping their customers, such as a new customer buying the product, only for a new release to come out a few months later.
From the perspective of Sales, they are happy to complete sales, but they don't necessary have complete control over when a product release will occur.