Historically the items I have sold via Ebay have usually been in the £500 plus range. Prepping and taking pics of an amp or guitar and loading them up can take me most of an hour if only doing one, but normally do a few things at once. Listing it, packing, dispatching, etc. can run me another hour easily once you consider dealing with messages, managing a listing, spending time on the phone with a buyer, etc., etc....
However, you will not sell at a favourable price unless you do the work.
With vehicles I have generally managed to take decent pics when I acquired them, but more time is taken up with test drives, logistics, etc.
Having been self employed or on a self employed basis most of my life, my time is weighed precisely. I would not waste any of it willingly, but sitting composing listings is something fairly relaxing, and it is no more than time others might spend watching tv or whatever. It is also very much at my convenience.
If we are left with fifty boxes of tat once all is done, they can go to the charity shop. Not too bothered, but you won't get your time back selling tat at boot sales anyway. I cannot be arsed haggling with grubby and smelly people over an incomplete tea set. Not for me the drudgery of paper labelling auntie's horrible vase she insisted was always going to be ours, so we kept it there in a box under the stairs to be rushed out onto the kitchen table when we heard the unmistakable squeaking of her stroller wheels coming up the ramp we were forced to build by the nanny state.
Saying that, I used to buy and sell just about everything including food at car boots back when I first moved to London. That was over a quarter century ago; and now it is not for me. The five a.m. frosty windows, bleary eyed, hope I am sober enough to drive after a heavy night out clubbing trip to the car boot; to finally wake up by the end at eleven or twelve after half a dozen bacon rolls and cups of tea had sliced our slender gains in two.
Ebay is the the global car boot, and you can do it snug in your lounge.
You can even wear one of these if you want, and drink some Horlicks.