I found this in our price matrix
Price Valid Type
6:20 SEK today 14:20 - All Customers
7:00 SEK 12 dec 01:00 - 2030-01-01 01:00 All Customers
So at this moment we have to valid prices, is it that easy that Commerce by default will pick the cheapest one?
When you save prices, Commerce will automatically optimize them. Your prices would end up like this (assuming today is December 15th)
Price Valid Type6:20 SEK 15 dec 14:20 - All Customers7:00 SEK 12 dec 01:00 - 15 dec 14:20 All Customers
So 6.20SEK overrides 7.00SEK because it was cheaper and their valid times overlap.
And yes, if all other criteria satisfies, then the cheapest price will be selected