All of the titles in the Gabriel Du Pré series by Peter Bowen are on sale right now at Kindle US. Not on sale at Kobo US, at least for now.
The first three titles are available in an omnibus that is on sale for $3.99.
link:
https://www.amazon.com/Montana-Myste...dp/B07C9D5498/
The remaining titles are on sale for $2.99 each.
link:
https://www.amazon.com/gp/search/?ta...price-asc-rank
So if you like the series, but are missing some titles, here's a chance to fill in..or to try it with the omnibus if you think you might be interested...