since you mention a Razr I assume you are looking for a GSM phone? The Samsung A900 will not work if you have a GSM carrier, although other than battery life, I actually like the A900 better than the Razr, and I’ve had both.
I’d try Craigslist.com for your area. I bought and sold my phones here. I wouldn’t deal with Ebay too much, as their protection (which extends to PayPal unfortunately) for buyers has really gone to shit these days. At least with Craigslist, you can look in your major city only, and deal with someone face to face when it’s time to buy. I’d recommend it, but make sure you check and test thoroughly anything you are going to buy “on the spot”.