Ramba, Arena Showman

As long as Ramba, Arena Showman has dealt
combat damage to a player this turn, spells you
cast cost {r/w} less to cast and abilities you
activate cost {r/w} less to activate.
{5}{r}{w}: Reveal the top card of your library.
You may play it without paying its mana
cost. If you don't, put it into your hand.