It’s worth selling stuff on ebay as your items can be seen all over the world, I sold some really crappy (I described them as rubbish and only put them on for a laugh) Lambretta legsheild badges to Malaysia. The guy that bought them was really happy with them. It’s surprising how others see your stuff, if you want a certain amount for something put a reserve price on it, otherwise you risk it going for 99p.
The post office run can be a drag, luckily I live a few minutes walk away from a main office, I don’t know if I’d bother if it was more difficult to get to.
If you sell a fair bit of stuff the fees can start mounting up, you don’t really notice them until they invoice you at the end of the month, so keep an eye on them.