Honestly, the only price point I would consider buying promo cards is at the DEC peg Burn value. Everything else will result in a near-sure value loss over time. The game right now simply is not worth wasting time and money on to play modern and in Wild you are better off just running a bot.
Sad to see this is where the game is at right now after 6 Years in it.
RE: What Price Point Would You Buy Promo Cards?