Echo is a triggered ability that triggers at the beginning of your upkeep step if the permanent with Echo has come under your control since the beginning of your lats upkeep. In other words, have you gained control of it since your last upkeep step began. This happens if the permanent entered the battlefield or it you gained control of it. When this triggered ability resolves you can either pay the Echo cost or sacrifice the permanent.

When Echo was first used in Urza’s Saga the Echo cost was not specified and the cost you had to pay was equal to the permanent’s mana cost. When Echo came back in Time Spiral, Echo costs were no longer always the same as the mana costs of the permanent they were on. The official Oracle text for all older Echo cards has been changed so there is an Echo cost that is the same as their converted mana cost.