How to add NFC to a cheap consumer product?
Pretty much your only option are NXP chips such as the PN531 (old), PN532, and PN544. The PN544 is the one in Samsung's Nexus S phone. 
Most NFC cards these days are MiFare-base and since NXP owns the MiFare IP (and doesn't license it to anyone else) their chips are pretty much the only ones around.
I'm working with the PN532 myself and it's not bad. You can talk to it via UART, I2C, or SPI. They're not that cheap (considering the monopoly) but aren't crazily priced either. 

Whenever she gets it back in stock, I'd recommend starting with Adafruit's PN532 breakout board http://www.adafruit.com/products/364 and have a look at the PN532's user manual and datasheet in the meantime.

As for communication with smartphones, that'll involve the Peer-to-peer communication mode of NFC. But if all you want is to pass static content, just get a bunch of MiFare tags from Alibaba or something; they won't be more than $0.70 depending on size and form factor. They are blank and can be programmed (and locked) via a cheap USB NFC transceiver. For that I'd recommend the SCM SCL3711.

Good luck!