cheaper alternative to Xbee with similar functionality?

After reading the article [urlhttp://arduino.cc/en/Guide/ArduinoXbeeShield][/url] on how easy it is to work with I found out that it costs around $20 USD just for a basic module. Some project ideas that I'm thinking of include putting a few wireless modules on devices and control them though my Raspberry Pi (mostly one way communication) which in turn I could remotely control through either SSH or HTTP. I would like something with similar functionality that costs less. A range of around 100 feet would be nice.

A range of around 100 feet would be nice.

One byte a week? 6 Terabytes per millisecond?

The XBee does error detection and retransmission. The XBees can read digital and analog sensors directly. Other radios can not. You can what you pay for.

PaulS:

A range of around 100 feet would be nice.

One byte a week? 6 Terabytes per millisecond?

Having a high data rate isn't important 9600 bps or even 1200 bps would be fine.

PaulS: The XBee does error detection and retransmission. The XBees can read digital and analog sensors directly. Other radios can not. You can what you pay for.

Those features are nice, but at around $20 a unit, costs quickly add up. I'm a little surprised that there are apparently no Chinese clones.

Now I'm looking at the nRF24L01, the price isn't bad :)

The price isn't bad, the range is about 10m, nominal.