Don't let appearances get in your way of PROFIT!
When I first saw Cara Ellison's post on Rock, Paper, Shotgun on how to spend $20 in Dota 2 while simultaneously making your characters look stunning, I thought it was a nice way to completely waste $20. Sure, there are some nice items on that list, but even Ms. Ellison herself recognizes that there's a decent chance that you will find these items either via the drop system after a match, or when opening crates.
I'm here to give you a way better approach to spending your hard-earned $20 on virtual goods. In fact, by this time next year you will probably have more money than you started with! Now, I understand that no one other than yourself can tell you how you should spend your money, but here's how you should spend your money.
First purchase: Dota 2
So, yeah. You'll kinda sorta need Dota 2 before spending money in Dota 2. But good news, this game is free! Now, unfortunately you can't just simply download Dota 2 from Steam yet, so you'll need an invite. A good place to go to is literally anyone on your Steam friends list, because they all probably have about 200 invites. If not, you can head over to the subreddit /r/sharedota2.
You know that game "Six Degrees of Kevin Bacon?" Well, this is basically "One Degree of Dota 2." You're never further than one person away from playing Dota 2.
Second purchase: The International 2013 Interactive Compendium
Buying this Compendium will accomplish many things. First off, it might make you interested in The International, which is the best tournament this side of the Internet. This Compendium allows you to make predictions about the tournament, March Madness style.
But the real reason you're buying the Compendium is for this little guy:
This is the courier you get after buying the Compendium, a Smeevil. He might not look like much, but during The 2013 International, he will evolve and probably become super badass. Regardless, this little bugger will most likely be worth a veritable butt-ton by this time next year. It's no secret that limited-edition items garner huge prices over time, with last year's Smeevils going for over 200 keys in price (that's a lot).
Now, it's a bit of a risk to assume that this Smeevil will be worth a whole lot next year, but that's how investing works! Risk vs. Reward. Since these Smeevils will "evolve" in some way over the course of time while watching The International, chances are each evolution will be rarer and worth more. Only time will tell, but chances are that if you have an evolved Smeevil next year, you'll make your money back on this Compendium, if you so choose to.
In addition to the courier, if enough people buy Compendiums, each Compendium owner will receive a "newly created Immortal item," which will almost certainly be worth a lot in the future. So really, it would be stupid NOT to buy the Interactive Compendium.
BONUS: HERE'S YOUR FASHION DAMMIT
If you've never bought anything from the Dota 2 store before, you'll get a set of items for Witch Doctor. FABULOUS!
Okay, I've got a Compendium, what else do I buy?
Keep it! You are now $10 richer than you thought you'd be. You're welcome.
And that's how you correctly spend $20 in Dota 2.