Biggest Non Purchase Card Regret

[Bambino22]

What is the biggest card ($$$ or sentimental) you almost bought that you will likely regret forever.

What pains you, that you tried to buy but missed.

And I'm specifically talking about a card you were very close to buying and not likely to own in future. Second on auction or you almost bought outright. Do not answer Mantle 52 unless you were actually close.

Answer the card and % you almost owned it. No explanation required unless you want.