How do you figure out postage costs? Particularly if you're selling a few things and could put together, or aren't sure how much it'll cost. Also, tracking or not?

Had bad luck with eBay but think forum selling might work ok.

Got loads of surplus to requirements stuff but never seem to get round to selling and thinking of dipping a toe in the water.

I use the royal mail website, you'll need to know the weight and size but if it's bikepacking kit you'll have the figures in your kit spreadsheet

sad but true

Various online ones have very generous size and weight option at certain prices so pretty easy to work out on there as well and then say postage discount for multiple items

The simple answer to the OP is think of a rough amount between £3 (smallest parcel) and maybe £15 (frameset) and if it seems reasonable just add it on to the amount you want for the item. If people don't agree they won't buy it! Sometimes you win, sometimes you lose but generally it's only £1 either way and for a £Tens item does it matter?

I've found Parcel2go website useful as a compare prices Vs size type thing.

I've found Hermes to be consistently cheaper than Royal Mail for a smallish parcel and I can drop it off at the local cornershop at 10pm too. The local garage also does Collect Plus which can be cheaper for medium size parcels (max dimension 60cm off the top of my head).

I almost never use Royal Mail now, sadly.

I use Hermes on the odd occasion that I do sell something.

I find buying much easier

Ok, thanks. Had bad experiences with Hermes for delivery so not sure but will look into the rest.

The Royal Mail standard parcel sizes / weights are pretty generous. A 'small' parcel will cost £3 second class and £3.60 for first.

As Paul says, Parcel2go can be useful for larger items as Royal Mail's pricing rockets for those things. I refuse to use Hermes and refuse to buy anything from anyone who does, as they flatly refuse to come here even though their delivery driver lives in Llanbrynmair.