I gotta disagree with not buying used items on eBay or even Craigslist, and going brand new. If you know what you're looking for in an item, and familiar with the prices locally, online, and suggested retail, you can find some killer deals or take advantage. Here are some examples of items I've bought and sold on eBay, and some on CL. Some may seem extreme, or even a burden to complete the transaction, but I always made or saved money, also factoring in my time invested.
Cell phones: when iPhone 3G first came out a couple of years ago, I sold my friends' used 2g 8GB phones after jailbreaking and unlocking. They sold for $350+ each to various states. When I got a 3G 16gb for $100 to extend my plan, I hacked it, and sold online for $550 with 2 days. Recession or not, didn't stop people from spending $600+ for a cell phone.
Home theater: I've bought all my used used definitive technology speakers, fronts, rears, center, online. Saving at least 65% off than what they went for locally. There is still risk involved, and you have to know what to ask before buying. My Denon reciever was $450, used for 5 months, normally 1100, and still included the extended 4 year warranty from Best Buy. Although I bought a $3500 new subwoofer for $750 on CL, from the owner of recording studio/reseller of high audio equipment, locally (who I later found out helped Prince produce his first album back in the day).
I bought a brand new PS3 for $300 back when they were 400.
Tools: The best $400 of rent income re-invested, went into a 6 piece brand new Dewalt 18v tool set, which went for 650 on Amazon.com at the time.
Laptops: I sometimes I'd buy bulk older IBM or HP refurbed laptops on CL from data recycler/warehouse. I'd test, fix, reload with free OS, and either sell on eBay or locally, staying above 50% profit of what I initially invested.
Cars: My friends and I have bought various cars on eBay, running, and not. But then again when we were younger, we loved road trips, so it was 2 birds with one stone. One friend bought an old CRX with no rust from FL, which he towed himself, for a project of his. Another time he flew me with him to Cleveland, to pick up an 05 Toyota Sienna AWD for his wife. The dealership was selling for $5000 less than in our state, and AWD was rare for that model, which he was looking for, for quite some time. I once took a took a U-haul truck from MN to Iowa to tow an 95 Integra with over $3500 of work put into the head alone (the GSR block had a bad crank rod), for $1500 on eBay. I knew I could make back the 1500+fees/gas alone from just selling the interior, lights, wheels, suspension, all online, while keeping the whole engine swap. Extreme, I know
A couple of years ago my friend had a customer at his shop who needed to sell his restored 1967 Volvo 1800S, identical to the one from the Saint tv show (too young for me). This car was beautiful for the condition, and had no mechanical flaws. I'd have bought if I could spare the $4500 he needed to get back. He couldn't find a buyer locally, and asked if I try online. It ended up going for around $8200 from an avid buyer from Denmark. I charged my seller $300 for the transaction since it was a lot of paper work for international transport, to complete under my name, and I had to open a separate savings account receive the money. It was a pretty interesting experience for my friend and I, to say the least, and I got paid for it.
Of course some these examples are rare, or pretty extreme. I've been more of a CL advocate for the last few years. But if you know what to look for, used or not, it can be to your advantage, while weighing the risk or potential scam. An item is only worth the amount you can find a buyer willing to pay for it. Ebay definitely has pros and cons, for various items, but it still hasn't died down as a phase for the rest of the world.