Should I worry about the cost per gigabyte when choosing between one 16GB stick or two 8GB sticks of RAM?

No, the price difference is usually within a buck or two, so it’s not worth overthinking. The real decision is performance versus upgrade path: two 8GB sticks give you dual-channel speed (especially good for Ryzens), while one 16GB stick leaves a slot open for future expansion to 32GB. Pick the layout that matches your build plan, not the per-GB math.