Since PGC has lost it's most popular buying option(s) and the others are a bit lack luster when compared, I've decided to ask around for suggestions on decent replacements and will be sharing some of them. #1: Offgamers is a website where you can purchase mint cards and turn them into PGC cards (via PGC's Mint option). They have Sales! #2: Mint Yep, the original site of the Mint cards. You can buy and sell cards here. #3: Alipay is a mobile payment app which you can download to purchase cards with (it's a chinese app, it is secured). #4: Dundle Similar to Offgamers you can purchase Mint cards here.
I recommend using offgamers for ease of access and slightly less hassle than downloading an app and going back and forth with codes.
Please keep in mind when you purchase a Mint card for VGN, Vendetta's website only allows a certain amount of money. Make sure to reference amounts before you buy so you don't buy a card that vendetta cannot accept on their website.
Thank you to @Jordan for giving me information to some alternatives.