1) 1st and foremost, don't buy an item that will cost you more to ship than it's worth unless you are going to resell it on Craigslist.
2) Counterfeit items or items that are heavily counterfeited without a receipt unless you know how to tell the difference and can prove it.
3) Expired items that will sell in the "Health and Beauty" section. You are going to see items such as Proactiv, anti-age creams etc. These are Great finds, but be sure and check the dates.
4) Medical Equipment requiring a prescription and/or not allowed on eBay. Example: 10's units (Electrical Nerve Stimulators), CPAP Machines & CPAP Humidifiers are also not allowed on eBay. BUT: CPAPS do sell FAST on Craigslist.
5) Obsolete Computer Equipment: Example: Single core processor computers, Full screen laptops, Old Fat laptops (except for Panasonic Toughbooks) Routers that have only a B range and most G range routers are also usually worthless.
6) Most Vintage Electronics: This is a tricky category and a specialty of mine. Most of what you will find is usually worthless. If you venture into this category a good rule of thumb is to stay with "High End" names. Educate yourself with names like Nakamichi, Pioneer and Sansui to start.
7) Stay away from used movie DVD's. I will do an update this week on desirable DVD's.
8) I shy away from used clothing and shoes unless I see something special like Leather Jackets, Disney clothing, Vintage Concert Shirts etc.
9) Knic Knacs, Statues and Home decor: Unless you know what you are looking at, stay far away. Low or No profit margin and a big hassle to ship.
10) Most Collectibles: Most are low value and cost more to ship than actual worth. There are exceptions of course, but you need to research before purchase.
11) Directv Receivers and DVR's: These are VERO and they will report you unless you can prove they were not rented. Selling their accessories is OK, ex: Remotes, Splitters etc...
12) OEM Car Stereo's: If you venture into this category, expect about a 40% return rate. These are Great profit, but you cannot test them. Do NOT buy these unless the seller can relatively prove to you they are the original owner and a good reason why they removed it from their car. IE: Removed because they upgraded to a DVD System or a Navigation System.
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Even thought this is a TOP 12 of what not to buy post, there are some things I included to be on the look-out for:
1) Leather Jackets and Vests: Especially Biker Style, Western and Native American. You should be able to get them for under $10. Try and stay away from the Pakistan and Chinese Leather Jackets unless they are Vintage or something special.
2) Vintage Concert Shirts and Vintage Belt Buckles Promoting the Music Bands and Artists are always good.
3) Vintage Tennis, Basketball and Skateboard Shoes are desirable, but they have to be a Top Name Brand and in Very Good Condition or New.
4) Medical Equipment: You are going to see 4 or 5 CPAP units and a year. These cannot be sold on eBay, but they sell FAST on Craigslist. You can sell the the accessories except for the mask and humidifier. Something else to note: You can sell the Humidifier Parts, but not the complete unit as a whole.
5) Directv Receivers and DVR's cannot be sold on eBay, BUT: DishNetwork doesn't seem to care. When selling these, be sure and sell them as a parts machine unless you can prove they weren't rented units.
This is what a common CPAP Machine looks like (but there will be several variations:
