Sparkfun: don't hold your breath, I have not seen the receivers there since August.
Try the $5 pair, or the next one up.
Want a simple transmitter? Get a "high" voltage, and let it spark to ground - then get a simple AM radio and listen for the burst of interference that comes in. Not really practical tho.
If you can make a circuit oscillate, it can be a transmitter, whether intentional or not.
Being able to reliably tune in that transmitter and pick out a piece of data is the hard part.
One way is to have transmitter is transmitting continuously and your receiver tuned into it, and then detect a difference in the signal and report that as different state.
If you're not transmitting continuously, that makes it harder for the receiver as now it not only has to tune, it has to determine the 2 seperate valid states.
That's the nice part about virtualwire, it takes care of getting enough sent for the receiver to do its job.
Designing RF that works from scratch without tools and the engineering background is very difficult.
Here's a simple thing you can tryhttp://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_p024.shtml