Barbamon

Q:Can I use this card's [All Turns] effect to play a purple Tamer card from my trash?

A:Yes, that's correct.

Q:What does "for each card in your opponent's hand, reduce this effect's play cost maximum by 1" in this card's [All Turns] effect mean, exactly?

A:It means that you reduce the maximum for the play cost of the card that can be played by this effect by 1 for each card in your opponent's hand. For example, if your opponent has 4 cards in their hand, you would reduce 10 by 4, resulting in a maximum play cost of 6, meaning that you can play 1 purple card with a play cost of 6 or less without paying the cost.