I would like to print midels taking advantage of Single LED Magnetic Control Switch Lights but $2.5-$5 each isn’t cost effective for me.
Is it possible to make this myself for less? Where should I start?
Certainly, you could design one of these.
You may get to a lower cost by buying everything from China.
I would start by completing a design on one of the free PCB services and then see what they would charge you for the BOM and assembly.
I use Easy EDA.