Personally, I would probably focus on budget decks, but put awesome value cards in them that I found cheap in boxes and trades
It can even help you find some creatures in your deck or make sure other creatures effectively die so you can reap some rewards
Here are the 10 Expensive Pokemon TCG Cards: Pikachu Illustrator : Price $5,275,000 Pikachu No.2 Silver Trophy : Price $444,000 First Edition Shadowless Holographic Charizard : Price $420,000 Prototype Blastoise : Price $360,000 Bronze Pikachu No.3 Trophy : Price $300,000 Ishihara Signed GX Promo : Price $247,230 Kangaskhan Family Event Trophy : Price $175,000 First Edition Holo Lugia : Price $144,300 Toshiyuki Yamaguchi No
That isnt a huge upside, but being able to get something into play in a worst-case scenario is still much better than a combo piece thats otherwise dead in your hand
The customization options extend beyond just the cards themselves
drake31415 didn't specify the playstyle for this deck