That seems cheap, but the you need the receiver also. rfRXD0420/0920 $2.89 from MicroChip. LQFP package If you are doing a production run they would be great.

But if it is a one or two thing....

The cheapest/ease of use I know of is these
http://www.rentron.com/remote_control/TWS-434.htm
http://www.rentron.com/remote_control/RWS-434.htm
All the need is an antenna and a PIC.
I tested some and had no trouble at a half mile line of sight.

Just my opinion.