CardName: Revelry Bard
Cost: {1}{R}
Type: Creature - Human Bard
Pow/Tgh: 2/1
Rules Text: At the beginning of each combat step, add {R}{R}. Spend this
mana only to cast instants or activate the abilities of
creatures you control.
Flavour Text: Folk Horror plane
Set/Rarity: temporary storage Rare
Revelry Bard
R
Creature – Human Bard
At the beginning of each combat step, add . Spend this mana only to cast instants or activate the abilities of creatures you control.
Doesn't seem like you need the extra restriction, since what else are you going to use the mana for at the beginning of combat?