Used Nuvis

They may be a little difficult to sell due to their age and memory size. The one advantage you have is that both of these units offer truck routes where anything after the 6XX series does not.

If you advertise on Ctaigslist make SURE you stress the fact the unit has truck routes for commercial traffic. In my area of Craigslist I see a regular ad for a 660 from the same seller that has numerous 660 units for sale, anywhere from the 120-140 range.
I think that's way too high. I would list the 680 at 75.00 and see what responses you get, if none lower it.

Also check and WATCH 650's and 680's selling on Ebay, see what they have been SOLD for, this will give you a gauge of the current value of the units.
Take into consideration the seller has to pay Ebay listing fees and Paypal fee's if sold through Paypal.

Also when and if you sell a unit that you have previously registered with Garmin, make sure you logon to your myGarmin.com account and DE-REGISTER the device. That way, the new owner can register it in his/her name.

That's a good point and will enhance your chance of selling. Make sure you state in your ad you are original owner and will remove your registration.
You can do it with the buyer present and them have him/her register it. It will give them peace of mind they are not buying a stolen unit.

If you never registered it and are the original owner, the new owner can just register it.

The registration really offers no benefit since no longer under warranty and still can be updated using WebUpdater. Since discontinued no firmware updates will be available on WebUpdater on units this old.

I am planning to sell me 255W. Didn't know this.

Before you sell your gps don't forget to delete any saved locations/trip logs and then reset the unit to factory settings. You probably don't want the new owner to know your home address!

I see an auction on eBay for a LOCKED nüvi 760. I don't know how someone gets a locked unit unless it's stolen. I know I lost one or had it stolen (never have been really sure which) and it had the Garmin Lock enabled. Hopefully the person who has it will never be able to use it.

I just have to wonder about auctions for locked units. The seller has excellent feedback which makes it even stranger.

I would never buy a unit with a locked screen, as you mentioned probably stolen.

The seller does sell used GPS's so this is not his first rodeo. Either he screwed up when he bought it and didn't see the locked screen, or more likely there is a market for them. He probably got it dirt cheap because of the locked screen.

Amazing, there are 7 bids on it with 5 different bidders who have extensive Ebay feedback.
Seems like these guys know how to defeat the lock or perchance buying for parts only.

Depends on the definition of "locked screen". My friend's Nuvi is in a perpetual "locked" status because the power switch (which doubles a display lock) is broken. He can switch it on with a power cable but it is unusable because the screen is always locked. Nuvi tells him to unlock the display but the switch just slides back and forth and does nothing.

I've sold several NUVI's on Craigslist and have had great success.

I have do the following before selling:

Update the unit to the latest software and road test several times before putting away in box.

Remove POI files

Reset to factory settings

Delete any personal data including music files (depending on your model.

un-register nuvi from Garmin website

In the Ebay ad the seller clearly states:
"" BUT THERE IS ONE PROBLEM THE SCREEN IS LOCKED AND WE DON'T HAVE THE PIN TO UNLOCK THE SCREEN".

In my area also see many in Craiglist with GPS only, no charger.

Yes, there is a market for used Garmin Nuvis. In fact, I just bought a used Garmin Nuvi 350 earlier this spring. Although there are definitely newer, more feature rich Garmin Nuvis avaialable, I had an ulterior motive. I bought a Uniden Home Patrol HP-1 scanner radio and it can be connected to the Garmin Nuvi 350 with a cable from Argent Data. That allows the Garmin Nuvi 350 to perform two functions:

-Automobile Navigation, and

-Providing NMEA-0183 Data To The Uniden HP-1

That allows the Uniden to change frequencies based on the location.

I was pleasantly surprised when my used Garmin Nuvi 350 arrived. It was eligible for a free map upgrade, so it now has CN NA 2013.1. I also added additional memory to it. It actually had a full size SD card slot. I used an adapter and installed a micro SD.

Thanks to everyone. Great comments and advice. You've come through once again.

I just purchased a backup nüvi 760 for $67 on eBay. They were selling for anywhere from $60 - $80 with ease. More expensive ones were available - including brand new for $400. I just wanted a backup in case "Jack" ever dies on me. There is definitely a market for this model so I'd guess your 680 and 650 would be items of interest to others as well.

That is something I have not thought about before, but also never sold my old one.

Yep. I received my used nüvi from eBay and it works fine but I wasn't able to register it because it was already registered. Fortunately a note to the seller resulted in him removing the registration immediately (he had merely forgotten about it) and I was able to register it in my name the next day.

When selling a used GPS removing your registration info from my.garmin.com is a good thing to remember.

And on newer nuvi models that came with lifetime maps, unregistering also invalidates the lifetime map subscription ... the new owner will not get map updates unless he/she purchases a new lifetime subscription. I think it is important to let buyers know in your listing of a used nuvi that lifetime maps are NOT included even though the model is LMT. I have contacted several eBay sellers about their listings and found many of them did not know or would not acknowledge this fact.

This comment of course does not apply to the OP, whose older nuvi's did not come with Lifetime maps.