Activate Blinking Spirit by paying 0, returning it from the battlefield to your hand.
Cast Blinking Spirit by paying 3.
When Blinking Spirit enters the battlefield, Mana Echoes triggers, adding at least CCCCC.
Activate Crossroads Candleguide by paying 2, adding .
Repeat.
If you control six or more Spirits, this combo nets infinite mana.
This clever loop relies on the zero-cost activation of Blinking Spirit to repeatedly bounce itself back to your hand, allowing you to recast it and trigger Mana Echoes anew. Because Blinking Spirit shares the Spirit creature type with itself, each entrance scales the mana output of Mana Echoes as long as you have enough other kindred support on the board. Meanwhile, Crossroads Candleguide acts as a convenient mana filter, turning the excess colorless output into the exact white mana needed to replay the loop.