You can pay hundreds of dollars if you have some rare baseball card from Topps or non-sports cards from Magic The Gathering or Yu-Gi-Oh
Set a monthly budget before you start and stick to it
If you control no monsters, or all monsters you control are Machine monsters you can activate these effects: You can Special Summon this card from your hand, then you can reveal 1 DARK Machine monster in your hand, and if you do, Special Summon the revealed DARK Machine monster from your hand, also its Level becomes 10, until the end of this turn
What I mean to say is that the deck has no set course of action and relies almost completely on the situation of the duel, which I like a lot
Add 1 Digimon card with [Vegetation], [Plant] or [Fairy] in one of its traits among them to the hand
A clear design allows your sealed case to stay visible while protected