What model box do you have?
There are some analog transmitters/receivers out there... but none of them will transmit HD signal unless you want to spend few hundred dollars...
Here is one HDMI transmitter kit... but you will need a couple of them to do 2 more TVs
Also you will need a HDMI splitter, so you can feed the TV and the Transmitter
Using the cheaper analog for less than $30 will not work.
One of the problems with a DirecTV or for that fact Dish Network is the box, when you connect to the Video/Audio out ports.. the box then goes into 480i mode (so every channel is Letter box), then there is NO HD on the HDMI port, once you disconnect the Video/Audio cables the box switches back over to true HD on the HDMI port.
and depending on the box, there is no more coaxial cable out (Channel 3 or 4) to connect to a TV.
So I what I am saying there is no easy way EXCEPT having 3 boxes, they do have some wireless units... but alas DirecTV charges for each box AND you need your own wireless router to interconnect all of them to the main box!