Highspire Bell-Ringer’s cost-reduction ability doesn’t change the mana cost or mana value of any spell. It changes only the total cost you pay.

Highspire Bell-Ringer’s cost-reduction ability can only reduce the generic mana component of the cost you pay for a spell.

Spells that were cast before Highspire Bell-Ringer entered the battlefield count. If Highspire Bell-Ringer was the first spell you cast this turn, the next spell you cast this turn is your second spell.

Highspire Bell-Ringer can’t reduce its own cost, even if it’s the second spell you cast in a turn.