** This post originally appeared at iPhone Life where Adam is a featured blogger

It hardly seems fair to call my iPhone 4S (released October 14, 2011) “old,” but pretty soon it’s going to be!  I feel like I just got it, but that’s the way of the world isn’t it?  You about take something out of the box and it’s already the “old” version.

So, how can a person with any sort of reasonable electronics budget possibly keep up with it all?

By selling your “old” stuff so you can get the new hotness, of course!

I’m one of these people who Absolutely! Must! Have! the newest version of stuff, so I’m obviously always preparing to sell something. This works out fine because there are tons of folks out there that don’t mind having an older version of a great product. We can help one another out.

One of the problems I have though is the timing. That’s the kicker right there because there are so many rumors about when things are coming out, you never know exactly how to time your selling. Take the new iPhone, for example. I’ve seen speculation that it would be out mid-to-late September. That’s like, a couple of weeks there!  If I wait until the new iPhone actually comes out and I sell my old one after that release, I’m going to lose out on some cash.

Last year, before the 4S came out on October 14, the bottom fell out of used iPhone prices near the beginning of September, which was a couple of weeks before the official announcement and three weeks before the actual release of the 4S. If things go the same way they did last year, this is going to be the case for this year as well.

What’s a person to do? 

Well, at Gazelle an offer on your phone is valid for a month. Right now, they’re offering about $290 for an iPhone 4S in perfect condition. This price fluctuates, so don’t shoot me if you go there and it’s different, guys.

What you do is you get an estimate on it’s worth, and that estimate is locked in for a month even before you mail it to them. You actually have a month to send it to them, and if they agree on your assessment of its condition, you get a check for that original estimated amount. So, you can conceivably hang on to it a bit longer before sending it off and still get a decent amount of money for it. This is what smart sellers are doing right now in order to lock in their prices: sell now, send later, be happy.

Being able to hang on to your phone for a bit before sending it off is a great option because what do you do for a phone in the meantime?  Sure you can plug your SIM card into something else for a while, but who lives like that? It’s unimaginable to me to be without my regular phone for any amount of time (unless of course that amount of time is spent getting to know a hot new number)!

Gazelle isn’t the only place where you can sell your phone. Other places include eBay, Amazon, RadioShack, and NextWorth.

At NextWorth you can get about $300 for a perfect iPhone 4S. The process works similarly to Gazelle, but you only have 21 instead of 30 days before the offer expires.

On eBay, you can either sell it right now for about $300 or you can wait and let it go to the highest bidder. You might get a few more bucks out of it if you let it go to bid. If your phone is in perfect condition and you are a patient soul, this might be a good option. Otherwise, instant sale might be a better idea. eBay has made this very easy for you by creating a fast way to list it, a secure way to ship it, and an easy way to get paid for it.

Over at Amazon, you can get a gift certificate in exchange for your old iPhone. They’re offering about $400 for a mint condition phone with charger.

RadioShack will give you a trade in value toward a new iPhone. For a fully functioning iPhone 4S you can get about $250 toward the purchase of a new one. You can either go into the store, or trade it in online.

This isn’t an exhaustive list, but it’s a start to give you a few places to compare before making a decision. Whatever route you choose, do it sooner rather than later. With each passing day, your “old” phone is worth less and less. Right now, there’s more demand than supply, but the longer you wait, the less true that becomes.

So, is the iPhone 5 luring you in too? Are you going to go for it? Will you be selling your old phone?  How many questions can one blogger ask at once?