Ebay is an easy option, especially if you can find a lot of items that people want, but its abit hit and miss and probably wont guarentee you a constant amount. but definately worth exploring and maybe start by having a look around the house for things that are nt needed or used any more,
As for the EBay shipping part, my local ‘proper’ post office opens 9 to 5,so wont work for you, but have a look around your area and there are 2 ‘franchise’ post offices near me run by local shop keepers and they open at 7am and don’t close until 10pm. I’ve posted items at 9.30pm and they just accept it and add it to the next days collection etc.
The other option for smaller items is EBay’s own delivery, which is currently run by Shutl, but this is changing very soon, and can be shipped via places like the Co-op etc, which again open 7am to 10pm, and they are reasonably priced too
You could also look at CollectPlus, DPD and UPs etc who all work with local shops (i.e. Spar etc) but they are all expensive, especially for smaller items. Other options are available, you’ll just need to research your local area to see what’s available and closest. You’ll need a few options depending on the size of the items etc.
Let me know how you get on and what you find available. Hope this helps a little.