Weighing less than 3 ounces, there's little out there lighter than the Versacarry ZeroBulk holster. With a steel-core retention rod, a wing to cover the trigger and a sturdy belt clip, it's about as minimalist as you can get and still cover the trigger.
One advantage to this system is accessories do not require changing your holster. Add a weaponlight? No problem. Rail-mounted laser? Yep, that will still work. Combination light/laser unit? Again, not a problem. The Versacarry is more or less independent of any accessory you might add to your handgun.
On the flip side, the method of retention—a plastic-coated steel rod inserted in the barrel—requires the pistol be carried without a round in the chamber (per Versacarry's instructions). This does necessitate a change in tactics to include charging the pistol as part of the draw.
MSRP: $24.99. The Versacarry unit is ambidextrous, as the wing that covers the trigger guard can be installed for either hand.