7th Singularity Babylonia: Cutah free quest is the best AP-saving & time-saving location to farm Ghost Lantern. You'll get around 3-4x Ghost Lantern by spending 210AP.
2nd Singularity: Mt. Etna free quest is the first location you unlock to farm Ghost Lantern.
Note: No Bond CE's here.
5 Star Servants Tier List
Best Servants [★4]
Christmas event [JP 2016 Rerun]
FGO Reroll Tier List
Holy Night Supper
Piece of Year 2030