I fixed tonight a problem with rfrpi and Raspberry 2+ ; it seems that wiringPi 2.25 have a bug with delayMicroseconds() function that works perfectly when less than 99us and do not work correctly with larger values.
Waiting for the fix the code have been updated to work correctly with RPI2+ ; so please if you are using the shield with RPI2+, update the rfrpi code from bitbucket.
RfRpi card is a RF433 emitter and receiver add-on of Raspberry Pi. This card is based on high quality receiver and transmitter I have selected after tests you can find here and here. This article describes how to get start with this shield.
To buy this shield the best way is to sent me a comment on this post, the price is 60€
The Shield is now working with Raspberry PI B+ and previous versions. The Shield is also working with Raspberry PI 2+. For these two last version you need to compile a kernel driver.