Although the original purpose of this thread has sort of gone a bit by the wayside since high-value Kobo coupons are hard to find these days, for those who are willing to travel, there is a 40% coupon for Kobo Taiwan right now -
see this thread.
And on the way to looking for other things, I noticed an omnibus of all five Grand Fenwick/Mouse That Roared books by Leonard Wibberley is available for NT $218.60, which my currency exchange site tells me is about US $7.20, which is a pretty good deal even without the 40% off. And with the 40% off, it's NT $ 131.16, or about US $4.34. The ISBN is 9781536564242, and the link is
https://www.kobo.com/tw/zh/ebook/the...ed-set-5-books, however, be aware you may need to already be in the Taiwan store for the link to work.
Just for comparison, the individual titles range approximately NT$ 120 - 140 at Kobo Taiwan, or US $4 - $4.50 at Kindle US, and the same omnibus is $7.99 at Kindle US and £6.18 at Kindle UK.
Anyway, having now given this ancient thread a bump, I'll have to think about whether I have found any other cool omnibuses recently