best wireless way to connect to arduino?

I've just started reading "Making things talk" and it showing how to connect to the arduino wirelessly via bluetooth. Is bluetooth the cheapest wireless way to connect? I'm a student without a whole lot of money to blow on learning about the arduino.

Remember that everything in life is a trade off.

Cheaper
Easier
Faster
Reliable

All these things are trade offs against each other.

This is probably the cheapest way to implement wireless
http://www.seeedstudio.com/depot/315mhz-rf-link-kit-p-76.html
They are not as reliable as bluetooth however - they tend to occasionally "drop" bits and occasionally think random noise is a real message.

Google "arduino virtualwire" to check out a library which makes communications using these modules more reliable.

The other thing you don't mention is what you want the arduino to connect to: another arduino? PC? mobile phone?

To a pc right now.

Right now it's between that and bluetooth. The other option would be xbee but I dont think that's a good idea if I could just do bluetooth and follow the book exactly.

What bandwidth? What distance?

BT can be high bandwidth and is short distance. XBee is low bandwidth (56Kbs) and
longer distances 300ft outdoors, line of site, 1mW. If you buy a radio module
you will pay $20-$25 for either one. The trade-off is bandwidth and distance.

The Blue-Giga BT modules are easy to use. The XBees are trivial to setup and use.
If you think you want to talk to your phone then XBee is out.

(* jcl *)

After discovering the seeedstudio store I found bluetooth can be done much cheaper than I thought. So I'm pretty sure I'm going with that. And it will all be done indoors within 20 feet.

Would this bluetooth module be compatible with the BlueSmirf module sparkfun has? http://www.nkcelectronics.com/bluetooth-module-serial-port.html Compatible as in same type of features just less powerful?