All these sites offer varying degrees of game goodness. Humble Bundle in particular allows you to pay however much you want and you can also decide how much of your payment is donated to a charity of your choice (hence, Humble.) That's cool! And that may be why Humble's bundles tend to sell a bit higher and deliver a bit better quality of games.
With Humble Bundle and Indie Gala, the more you choose to pay, the higher-tier games you unlock. Here's the breakdown of Humble's current Devolver bundle.
Tier 1 — Spend $1 or more
Humble's latest offering is true, true, true to this policy. Donate one dollar to get a Steam key for Ronin, Fistfull of Gun and Gods Will Be Watching. All of these games look slobber-worthy and Gods in particular delivers a quality pixel gaming experience. I published a preview of it a few weeks ago when it was on sale on Steam. I suppose now I should write a follow-up review to at least let you know some good reasons a dollar for this game is an absolute steal!
Tier 2 — Spend $4.10 or more
Not a Hero looks amazing! Shadow Warrior Special Edition and Dropsy also look great.
Tier 3 — Spend more than $10
A little dubious about this tier. Hatoful Boyfriend: Holiday Star probably appeals to the anime crowd, but it is $10 on Steam anyway. And Titan Souls looks really nice and normally sells for $14.99, but reviews insist it is insanely difficult. And for a casual ghetto gamer, that can be frustrating. But don't forget that $10 will get you every single game in the bundle. And that's a Ghetto Gaming deal!
Playing it cheap,
the Ghetto Gamer