Colin Johanson, lead content designer, Guild Wars 2 wrote ...

Correct, there is a cash shop that we run for the game. One really important thing to note is, we don't ever sell anything in there that makes your character more powerful. That's really important to us.

We like to do the - Is it Evil? test. Every micro-transaction that we do in the game, we have everyone in the company look at it and say Is it Evil? Is it really something we should be selling?

Generally, the stuff in our store is purely cosmetic; it's bonus stuff, it's extra stuff you can get if you want to, but it's not stuff you have to buy to play the game.
Guild Wars 1 famously carried no monthly subscription at a time when they were rife. Money was recouped through sales of the game and its expansions and, later, through the micro-transaction cash shop.

If people want to support our company and want to purchase that stuff, there will be more options for them to do so.

Colin Johanson wrote ...
We not just hope, we believe a lot more people will play Guild Wars 2 than they did Guild Wars 1, and we think that that will offset a lot of the development costs in itself.

We certainly are putting a lot more work into having more things available in our online store. The Guild Wars 1 store worked for us, it's been there the whole time, but it didn't have a ton of stuff in it. The Guild Wars 2 store we're working on having more stuff for you to pick from to buy.

If people want to support our company and want to purchase that stuff, there will be more options for them to do so. And it's totally up to them.

We anticipate that that will help us, too.