Digital Cameras: Gazelle
Gazelle listed the best prices and accepted every camera we threw in its direction. A Fujifilm FinePix F200EXR, for instance, commanded $87 in good condition; that's $9 higher than BuyMyTronics's offer and $23 higher than eBay Instant Sale's. For digital SLRs, you have the option with many models to trade in the lens as well as the body.
On the downside: On occasion, Gazelle requires that you sell a DSLR's lens as well as the camera body.
Runner-up: If you're trying to sell just a DSLR body, eBay Instant Sale may come through where Gazelle does not. The Pentax K2000, for example, sells for $127 without the lens through eBay Instant Sale and for $160 with the lens on Gazelle.
Dishonorable mention: Best Buy, BuyBackWorld, and YouRenew don't accept cameras at all. RadioShack does, but its deals are terrible. A Canon EOS Rebel XSi can fetch $185 on Gazelle, but only $103.43 through RadioShack.
TVs: Best Buy
The buyback market is not kind to televisions. Most online services won't accept them, leaving Best Buy as your main option, and the price you get for them ranges from 50 percent of original value within six months to 10 percent for a two- to four-year-old set. The up-front cost is only $60 for a sub-$500 television, but for TVs priced at $2500 and up, Best Buy demands a $300 prepayment to enroll in the buyback program. It's an option if you're terrified of eBay and Craigslist, but not a particularly good one.
On the downside: If you keep the TV for a while, you'll end up with very little compensation at trade-in time. For instance, a set originally priced at $1100 will net you only $10 after two years; and you'll lose $10 on a TV that cost $500 originally, once you factor in the $60 up-front cost. Also, Best Buy pays only in store credit.
Runner-up: RadioShack accepts a limited selection of televisions 42 inches and under. Most HDTVs from major brands trade for around $100.
Dishonorable mention: None of the other online services deal in televisions at all. The playing field is wide open.
Game Consoles: Gazelle
Once again Gazelle offered the best prices on average, but most surprising was its $80 offer for an original 20GB Xbox 360, which probably should be worth close to nothing. Haven't they heard of the Red Ring of Death?
On the downside: Searching for your console on Gazelle is a pain, because typing "Xbox 360" brings up a huge list of games that you can trade in, too. Use the 'gaming consoles' category link from Gazelle's home page instead.
Runner-up: BuyBackWorld offered $96 for an original 20GB PlayStation 3, compared to a puny $66 at Gazelle.
Dishonorable mention: Nintendo's DS Lite doesn't command a lot of trade-in money these days, but RadioShack's offer was the most insulting at $14.68. BuyMyTronics's offer of $15 for the PlayStation 2 Slim was just as bad. In comparision, Gazelle offers $36.
Blu-ray Players: Gazelle
Most trade-in programs don't accept Blu-ray players. Gazelle does--it's as simple as that.
On the downside: Don't expect a lot of cash in return. Samsung's BD-C7900, for example, costs $300 on Amazon but will generate only $125 in trade. If you have a two- or three-year-old Blu-ray player, you'll have to recycle it or try your luck with Craigslist or eBay.
Runner-up: RadioShack accepts some Blu-ray players, but the value's much worse than at Gazelle. LG's BD590, for instance, is worth $119 at Gazelle but only $56.16 at RadioShack.
Dishonorable mention: Everyone else. You might expect eBay Instant Sale to accept Blu-ray players, but no such luck.
The Bottom Line
Though we'd like to recommend one trade-in service that consistently trumps all the others, there's no clear winner across every category of tech products. Gazelle fared best on trade-in values for most categories, and it offers the greatest number of payment options, but it won't give you top dollar for smartphones and tablets.
For its part, NextWorth wasn't especially noteworthy in any particular category, but it does give you the option of trading in gadgets at Target and J&R in exchange for gift cards. RadioShack accepts trade-ins at its retail stores in exchange for credit, though its trade-in credits tend to be miserly.
The primary takeaway, then, is that you should be aware of all the trade-in programs at your disposal, and check each one when it's time to sell your next gadget. And the next time a Best Buy clerk pitches you on the store's buyback program, we recommend that you walk away.