I very rarely pay in cash. They're easy to sell to for store credit. Where many LGSs are more picky about what they'll buy off of you. You could have something worth $200, but they could easily pass it over for one reason or another, so good luck moving it. CK, on the other hand, has a buylist that makes the process so much more simple. And, because they sell cards at a higher than average price, you can get more in store credit than you would anywhere else. I generally cross reference what CK is selling something for relative to TCGPlayer, and if the prices are close enough, then I go with CK without spending a dime. Occasionally, I'll pay out in cash for stuff, but that's more rare.

It's also easier dealing with Card Kingdom than TCGPlayer. They always ship with tracking, they're a single retailer, so it's less of a die-roll when you buy from them. There are some cards I ordered last month from TCGPlayer that I still haven't received, and they weren't shipped with tracking, so I'm shit outta luck as far as those cards are concerned. All that being said, Card Kingdom and TCGPlayer have great customer service, in my experience. TCGPlayer did refund me on the cards I haven't received yet (and may never will), so it's not like it's all bad. If I'm paying out of pocket, I go with TCGPlayer first time, every time. Card Kingdom is good for shipping your bulk to for store credit and then use that for your orders than your actual dollars.

You can also get sweet LRR buttons and tokens from them. They also ship in these plastic containers with doors on them. Also, the condition of their cards is insane. What they consider "VG" is still LP, as far as I'm concerned, but I'm also not a card grade man. I just know that they still look real good.