Did anyone mention -

    www.linxtechnologies.com

They have modules from as little as $US5.60 for a TX and $11.60 for
an RX (in 1's - prices reduce in volume) with >350 foot range and
5KBps data rate through to $23.80/$34.88 units with claimed >1/4mile
range and 50 KBps.

Don't know how good their product is but it looks good (pictures and
data on website) and they have a large quantity of tutorial material
and regulatory information.