In so far as there's a "right answer" for the pay-to-win parts of the game, this is it. EDH, in general, is much gentler on using cards that aren't the best and most expensive thing around.

I have a tourney-competitive EDH deck that, according to current prices, costs about $400. That's a good bit... but replacing 4 cards with cheaper counterparts brings it down to $63. And I have recently seen at 2 other good EDH decks under $40 from someone who decided he wasn't going to spend more than $50 on any deck.

Definitely doable.