I admit it. I got greedy.
I saw this PTC ad on CryptoWin and thought, why not? CryptoWin had just started a promotion of their new investment policy (I loved the old one, the new one is a bit pricey). They could be running another promotion. The website was commerce.coinbase.com, which I thought added legitimacy.

(This is not the original ad, but what I captured after the fact, but it's close enough for everyone else to recognize this scam)
Immediately after I went through the process of sending some Litecoin (BTC fees were too high), I thought some more about this "promotion".
CryptoWin only deals in BTC. Further, CryptoWin works with FaucetPay, not Coinbase.
Then I knew I had been taken. But I still checked my CryptoWin balance for the next hour, hoping against hope, that my funds would show up.
Then I saw the same PTC ad on Cointiply, but using Cointiply's logo.

I'm not going to get my Litecoin back, but at least I can keep someone else from falling for this scam and that's good enough for now.
I would not be surprised if this scam PTC ad shows up on some other popular sites.
I'm not going to stop using CryptoWin and Cointiply, they pay too well, but I not going to let greed tempt me into another scam.
It shouldn't need to be said, but here it is: This is neither financial nor legal advice. Do your own research (DYOR). Stay safe out there, fight the good fight, and keep on stacking satoshis!