To the best of my knowledge these are not limited time offers, but the folks at Jackvance.com have been putting together omnibus editions of his books.
The recent addition of the
Cadwal Chronicles Omnibus caught my attention. The omnibus is priced at $15 -- the three individual books would cost $20. I really liked the first book in the series, Araminta Station, when I read it many years ago, and you can read it as a stand-alone novel ... except for a cliffhanger ending that he tacks on. The second and third books are very good, too, and do help tie up loose ends.
The good news is that these ebooks are DRM-free in .MOBI and .EPUB formats from Jackvance.com. (They are also available at Amazon and Barnes & Noble if that's more convenient.)
The bad news is that there do seem to be some Geo-Restrictions. I'd really, really love to have the Dying Earth Omnibus, but it seems not to be available in the US.
The list of all current omnibuses from Jackvance.com is located
<HERE>.