I suppose that's very true that people who know about all that stuff don't really want to buy what I'd sell anyway, they'd already have it

Well in my area there's a lot of people dealing in laptops and PC's (We have a Desktop guy here in town apparently...they're all junk computers but he's selling 'em apparently) and idk how well those old ones would hold up in the market...I'm currently looking at this posting (
http://milwaukee.craigslist.org/syd/3902428119.html ) and the guy deals in laptops out of the milwaukee area :/...That's the out of the box price on that Laptop and it's a refurbished unit w/o the box used -.-...I believe that this laptop should sell for $350 with 8GB ram and a 500GB HDD....is this reasonable?
The thing with desktops/laptops is that you can get a brand new, entry-level Dell for $350/$400 respectively. Even professionally refurbished (stripping the system and cleaning everything, replacing what needs to replaced - which the guy you mentioned may or may not do, though I'm erring on the side of 'probably not') will run that much, and rarely include a warranty (although the person you linked to does, albeit limited) unless it was done at the factory.
What laptop are you talking about - the one you linked to in the above quote or the example referenced in post 6? If the #6 one, provided the case is clean, nothing dinged, inside is properly cleaned, fresh OS install, and all the ports and whatnot is working, I would say in the $275-$325 range. Someone will buy it in that range, but since people's needs for specific applications of the system and their personal tastes are subjective, who's to say when it will sell (but I firmly believe you'll get a solid $300 (if not a bit more) if you hold off long enough - list it at $330 and let them think they talked you down, it's not at all uncommon). It's not clear-cut since it's not brand new. Need to be mindful of that too, some people equate a clean, sleek system with performance; others don't care what it looks like, just so long as it runs. If you're going to do a handful here and there just for a bit of extra cash or for something to do (as I think you are), rock on. Any dreams of earning enough to live off of though need to be re-looked at - it's actually a fairly cut-throat business to get started in unless you're already established either in the community (mom and pop shop), or a serious on-line player (Newegg/Amazon).
(Edit for above paragraph's end: Or have a serious marketing plan and a ton of time to devote to it, as well as enough cash on-hand to warrant buying entire lots from a business that went under or a town/city used office equipment auction, both of which are crap-shoots on what you actually get, and if it's from any type of gov't. auction, the HDDs are most-likely removed, so that's an added expense. Have to factor in a sizable storage area too with bulk purchases like that - closet won't cut it, garage might not either depending on much other stuff you have in there.)
Whatever you end up doing, remember that the end product you sell is a direct link to you. Give crap, earn crap; give good, earn good.