I don't remember how it went last summer but lets say I don't pick up Bastion during the time period of the 20 - 27th (I'll be on vacation right when it comes out) and the next game ( Dust) comes out.  Is Bastion going to stay at its price or will it jump up in Microsoft space  bucks. Like once its not the featured game will it cost 5 bucks more?

The correct term is "Space Euros" 

No, that will not happen

@Vitalogy11: Ya in the last summer of arcade that never happened.

I only remember that happening with Meat Boy.

yea, Bastion is launching at $15 or 1200 microsoft points, at least according to Major Nelson's Blog. So no, you won't be paying more if you wait to buy it.

It's already at the 1200 point mark.
 
If anything it would go on sale for 800 during the fall.

That's only ever really happened with Meat Boy, and they made that all very clear that the $10 price was a special launch price right from the beginning. They haven't said anything about it for Bastion, so I'm sure that won't be the case.

It won't go up, but there is reliably an Xmas sale that includes most of the good games. If you really need to save $5 and don't mind missing out on the popularity wave, try waiting till then.

No. It's 1200 points. Asking 1600 points for Bastion would be madness.

I'm probably going to pick this game up once it's on sale for 800 MSP. Call me cheap, but I think €10 is the sweetspot for XBLA games.

$15 aka 1200 MS points seems reasonable for this game.