No idea if it is a good price but I think Excel Sports has the right idea in putting together the bundle below. They clearly understand that people are asking for lower gears.
It could be a solution for someone looking for a little extra on the hills and thought I'd point it out. Upgrade that 28 tooth cassette to a fully supported 34 tooth solution with a click of a mouse.
Ultegra R8000 3-Piece Wide Range Upgrade Kit
GS Derailleur, choice of 11-30, 11-32 or 11-34 cassette and chain - $187
https://www.excelsports.com/upgrade_...groupType=road
-Tim-