QSLs - Why no IRCs?
Discussion amongst many DXers in NA/SA have shown that the USPS is making it VERY hard to encash IRCs since 2007-01-02. 

In fact, although they are supposed to sell them, they have no idea what they are.

QSLs - Why SAE?

 Always send a self addressed envelope it makes returning a QSL to you VERY easy and VERY much less prone to errors. 

Senders address on the top left of the envelope. If you put your own it will freak out the USPS (since 2001-09-11 they delay or destroy many sent this way). 

I have my own stampers and if you put your address there, I will just have to black it out anyway. Don't print the image to the left, I will just stamp out my address and the Air Mail impression anyway.

It makes life much easier if you include a self-adhesive envelope. It saves those tongue paper cuts which are truly awful. Buy a supply of them, other DX stations will like you for it.

QSLs - Why so much money? [Everywhere outside the USA is now $1.50 per envelope]
 The cost (at the lowest price possible) of a full colour QSL card is US$0.08. If you send US$2 and SAE it helps a lot!!!! Sending one from VP9 costs well in excess of US$2. A very complex calculator for USA mailing can be found here.

QSLs - Why no bureau?
I'm not a member of a Society which receives & sends bureau cards.

QSLs - Why none sent out from me?
I gave up DX chasing at least 20 years ago. If you want a card, you'll get one, but I don't send any out unless I receive one first.