Like most Pokmon cards, the value of Porygon-Z depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Unbroken Bonds)
Aside from the artwork, the layout of Japanese Pokmon cards often includes more text and information, such as the illustrators name and card description
Destroy target artifact or planeswalker
Some things that may draw you into specific colors are: A really strong rare you're excited about Plenty of "removal" cards that can deal with your opponent's creatures A lot of playable cards in that color A good "mana curve" in that colormeaning lots of creatures of different costs Ideally, the colors you pick will have all four, but if two or three of those are true that's plenty good
Cardhoarder Cardhoarder is my second option when it comes to buying cards with tickets, but my first when I buy tickets themselves and purchase cards with real money