Kind of a bad news, good news status update.
On Sunday, only the second day of the year!

I fell prey to a good value on a book of some interest. And then today, I caught myself investigating a couple of intriguing prices and finally said,
STOP. So not only did I back off, I contacted Kobo CS and returned my Sunday purchase. (Pity I didn’t buy it at Amazon, which is where I saw it anyway.)
So the slate has been wiped clean and I hope I’ve both learned a lesson (again!) and that success will breed success. Because I really don’t need more ebooks.
(On a related but OT note: I also went through my holds at OverDrive and canceled most of them - the ones of less than extremely high interest. If it’s a book I really want to read, lowering my TBR rather than reading a borrowed book becomes a foolish goal. However, the problem with library books and one I’ve had my entire life is that the nature of due dates pushes the books I want to read most down the reading queue behind marginal books that need to be returned.)