Be smart about selling your old smartphone.

The new iPhone 8 is expected to be unveiled Tuesday, but before you even consider buying Apple’s most expensive phone yet for a reported $1,000, there’s some serious cash to be made from your old iPhone.

There are many options — you can trade your old iPhone for cash or credit, sell it back to the carrier you bought it from or sell it directly to a potential new buyer.

“Selling it out right would be the most lucrative,” online shopping expert Brent Shelton tells Moneyish.

“Unlike simply trading in your phone, to sell your phone, or most anything of high value, outright, you need to publish the deal on your chosen platform like ebay or Craigslist. If it’s an auction, you’ll need to wait until the auction finishes. You may also want to do some pre-sell research to get an idea of what others are selling their phones for,” he suggests.

Shelton notes it could take weeks to get any traction from potential buyers, so be prepared to wait.

“You could also offer it up on Facebook. The danger there is you have to deal with whoever is  buying your phone, but you’re not paying any third party fees.”

If you want to make the most back, try eBay, Shelton suggests. The e-commerce site has a “What It’s Worth” tool that lets you type in your phone model, color and storage that tells you a current trending range for a selling price for your phone ($694 to $832 for an iPhone 7 Plus), and you can lock in the sale price once you post your listing. For an iPhone 7 Plus in “like new” condition with 265 GB, you can get up to $741. That’s $100 more than the same phone selling on Craigslist for $650. Similarly, buying and selling apps like Offer Up allow people to sell products for however much they want and communicate with potential buyers through a built-in messaging system to negotiate price and delivery. 

“Another way to do it is trade in for credit. Apple and Best Buy offer gift cards you could use towards the purchase of a new phone,” says Shelton.

Apple’s trade-in program can give you a gift card for up to $375 for an iPhone 7 with 32GB. And you can get $215 in an Apple store gift card for an iPhone 6s. Best Buy on the other hand will give out $380 for an old iPhone 7 Plus.  

Other options are third party retailers, like Swappa, which offers $665 for an iPhone 7 Plus. Gazelle.com,  a company that buys and sells pre-owned electronics, gives out $340 plus a $20 store credit for the same phone. And trade-in service Nextworth boasts $350 for the same phone.

If your goal is to make more money, don’t consider trading your phone back to your carrier unless it’s damaged or you want to start a new plan with a different phone company.

“If you’re going to do a trade-in for cash through the wireless carriers it’s not going to be the biggest amount to get back,” Shelton admits.

“But if it’s kind of a damaged phone, you might as well just trade it in. It gives you a bargaining chip, especially if you’re going to a new carrier,” suggests Shelton.

Wireless providers like AT&T, Verizon, Sprint and T-Mobile all have iPhone trade in-programs. For an iPhone 6 with 16GB and in good condition,  AT&T will give $97; Verizon will give $110; Sprint offers $70 and T-Mobile gives back $91. And for the iPhone 6S the phone companies will give back up to $145.

“It’s the easiest way out if you’re going to upgrade. You just take it into them, they’ll show you a price they’re willing to pay and you’re done,” says Shelton.

But whatever you decide to do don’t wait.  It’s estimated that the value for used iPhones drops 10% in the two weeks after a new iPhone launches.

“The sooner you do it the better. It’s like buying a used car, the longer you wait the value drops significantly. It might make a difference in 30 or 40 bucks,” says Shelton.