There is no referal link involved, but I'd greatly appreciate if you guys ever decide to use mine on whatever site I recommend.
Bitskins - https://bitskins.com
This is it. Your only stop for steam wallet funds. Use block trades to transfer Ethereum to your onsite wallet, which will immediately convert it to USD site credit when it gets there.
After logging in with your Steam account, click on your balance 
Sounds simple, right? What can I tell you, I'm very good at explaining things.
My review
I use it pretty much on a daily basis. My only complaint is how some crypto withdrawals from the site take longer than I wish they did when the market is volatile. Everything else is great.
The interface works as it's supposed to. You can deposit using many g2a payment methods which is great if you're not banned for using a family member's card instead of your own like I did. They also take credit cards (this one only after id verification), skrill, in BTC, ETH and LTC.
You can only withdraw balance from sales, but you can withdraw to paypal, eth, ltc... Btc too but it has a very high fee (10 USD), while the others are as low as 0.25 USD / 5%, plus the minimum for these is only $5.
I use it to sell off, say, team fortress 2 keys, then withdraw $5 to paypal (getting $4.75 in paypal funds) and get something from, say, humble bundle.
The customer support is great, too. I raged a couple of times at them but they were civil anyway. I have no plausible complaints, they're the best around of this type.
Thank you for reading!