Blue Tacho Lighting

Hello guys, have an Omega B and would like to switch the speedometer and switch lights to blue. Does someone know how to do this cheaply ? There are indeed LED ́s that you can exchange for the pears, but I heard they are supposed to be black expensive (a LED should be at 6 Euro). Man, there is fast 60-70 Euro on the back!!! And with lamp color should not be exactly the hit !?! Maybe someone can help me here further ?? Gruss mic