Here is a “home-made” model drill set which I put together following a clinic at our local NMRA meeting (Thanks, Rich Breton!). I’m glad I did, it has made the task of drilling small holes simple.
This is a battery-operated General Tools model 500 screwdriver. It uses 2 AA batteries. A drill chuck from Micro-Mark fits right in. It turns very slowly, so slow you can see the fluting on the drill bit turning; perfect for drilling plastics. The control reverses the direction of turn, the speed is fixed.
About $65 set me up with everything.
Micro-Mark 82727: 20pc drill bit set, #41-#60 $19.99
Micro-Mark 26104: 20pc drill bit set, #61-#80 $10.99
Micro-Mark 86259: Drill chuck $16.99
General 500 Precision Cordless Screwdriver, about $19 at Lowes or Amazon
Also note NMRA members get a discount from Micro-Mark.