Most of this category packs like any other fragile object. The part that is different is the battery, and it has to be dealt with before the sale rather than after.
Ask the courier first
Couriers restrict lithium batteries. Some will not carry loose cells at all; some will not send them by air; some want them declared. The rules differ between carriers and services, and they are not something to discover at the counter with a sold item in your hand.
So: find out what your courier does with batteries before you set a delivery price, because the difference comes off your own balance and not the buyer's. How delivery is charged.
If a device cannot sensibly be posted, collection is the honest answer, agreed before bidding.
Then pack it properly
- Device powered down, not in sleep
- Screen protected with a soft layer — a cloth or tissue first, so nothing textured presses into it
- Bubble around the whole device, taped so it cannot unroll
- Cables and adapters bagged separately, so connectors cannot press into a screen or a case
- Box close to the size, voids filled firmly
- Seams taped
Things that need their own answer
Screens — the single most commonly broken thing in this category. Rigid protection on both faces, not just padding. Hard drives — treat them as fragile; a drop that a case survives can kill one. Components and boards — anti-static bag, every time. A board posted in a plain plastic bag can arrive dead and look fine. Anything with a fan or a disc — nothing loose inside it.
Say what is in the box
A line in the parcel listing the charger, cable and anything small enough to be thrown out with the filling. People do throw them out.
Questions people ask
Can I post a phone at all?
Generally yes, as a device with its battery inside it. The restrictions bite hardest on loose and damaged batteries. Ask your courier.
What about a swollen or damaged battery?
Do not post it. A damaged lithium cell is a hazard and most carriers refuse it outright.
Do I need an anti-static bag?
For bare boards and components, yes. For a complete device in its case, no.