The annual subscription refers to the 1 year period you are eligible for free upgrades, access to betas, and access your program files at Stardock to download them.  If you download the .exe program installers from your account page and keep them archived and keep your product key (just as you would with any other downloaded software), you can continue to install them after your subscription expires.  Any programs you have installed will also continue to work after the subscription expires.  For more see here:

https://esupport.stardock.com/index.php?/default_import/Knowledgebase/Article/View/1/112/what-is-object-desktop

I believe there was offer of humble bundle on Stardock product. You can sign up for it here : https://www.humblebundle.com/games/stardock-bundle and get the notification when it start again.

Apart from that there is none that I know off.

Thank you,

Basj,

Stardock Community Assistant

I should probably point out that purchasing standalone would still not entitle you to every version of that product in the future.  It would be minor version changes only.  So you buy 2.01 and you get all the 2.x series but if we made a v3 of a product then it would be an upgrade potentially.