most people buying use the search based on title, so pack the title with as much relevant info as possible, put in both say 24-70mm and 24-70 mm to get people that search for either, make sure you have 'camera' or 'lens' in title as it is often missed.
ebay for me
When buying dont put in camera or lens as often people sometimes miss it and then miss the main searches so end up cheaper. You are sometimes better off leaving the search more vague and choosing search description (and/or do multiple searches with different terms) and then narrow search results on price and location.
Use the wildcard * and the -'ve to remove stuff you dont want
so if I want say a sony 24-70mm lens, I quick check shows me (ebay australia) the cheapest new is $1575 so set a search for
sony 24-70* with price set to between $1000-$1550 and search 'description' and 'worldwide'. That way I've got rid of the filters etc, the tamron and sigmas and the new ones. Those on bids below $1000 will turn up before they finish if they are decent. And I am seeing all the variants of titles etc.
If you dont mind older lenses, sometimes they still have a camera attached
