By Louis Ramirez, dealnews senior features writer Buying a new smartphone shouldn't be a major expense. In fact, it shouldn't be an expense at all. Our dealnews archives show that months after a phone's release, you can snag that same handset for free (contract and data plans required). But which smartphones hit the $0 mark the fastest, and is it ever possible to get an iPhone for free? We tracked past deals on popular handsets to predict how long before some of today's hottest models are handed out for free. Sprint's HTC Evo The Previous Model: In March of 2010, HTC's Evo 4G became the first 4G smartphone to debut on Sprint's network, and it was sold directly from Sprint for $199.99 (after a $100 mail-in rebate). Three months later we posted our first deal on the Evo 4G: $200 with free shipping and no rebate hassles. That following September, the smartphone dropped again to $180, and by Black Friday the phone had already slipped to $100. This June and July we finally saw the Evo 4G hit $0 with no rebates via Wirefly. Overall, it took eight months for the phone to reach 50% off and 16 months for it to hit $0. The Current Model: HTC's latest iteration of the Evo — the Evo 3D 4G — debuted from Sprint on June 24 with a similar $199.99 price tag. This time, however, the deal didn't necessitate a mail-in rebate. And unlike the original Evo, we actually started seeing deals for the Evo 3D before its release. In fact, 16 days before the phone's official release, both Wirefly and Amazon Wireless offered pre-orders for $180 with free shipping. The Prediction: While that's only $20 off, it was the fastest discount we've seen on any HTC Evo smartphone, which in turn could be a sign that this phone will reach the $0 mark much faster than its predecessor, and thus well before the 8-month mark in January 2012. Current Best Price: $149.99 with free shipping at Wirefly, lowest by $50 Verizon's DROID Series The Previous Models: The DROID was Motorola's first Android-based smartphone. It debuted in November of 2009 for $199.99 on Verizon Wireless. Within hours of its release, we saw this highly sought after phone drop to $150 via LetsTalk, and a few days later it dropped again to $120 via Dell Mobility. By January 2010, it was nearly 50% off ($110), and by May 2010, it hit $0. Like the original DROID, the DROID 2 (which debuted in August of 2010) saw instantaneous deals. A day after it's release, its price dropped to just $75 via LetsTalk. Just two months later, it hit the $0 mark and remained at that price point through February 2011. So whereas the original DROID took seven months to hit $0, the DROID 2 took just two months. The Current Model: The most recent Motorola smartphone in the DROID family is the DROID 3, which was just released in July for $199.99 from Verizon Wireless. A day later, it dropped to $50 via LetsTalk, making it one of the most discount-friendly DROID phones we've seen. The Prediction: We wager that the DROID 3 will hit $0 in mid to late September. Current Best Price: $59.99 with free shipping at Amazon Apple iPhone Deals Unlike its competitors, Apple has kept an iron grip on the pricing of its iPhone, which means you're not going to see deals on the forthcoming iPhone 5 for quite some time — but after its release, you may instead be able to score a past-generation refurb for $0 (if you're patient). The Previous Models: Take for example the iPhone 3GS. It was released in June of 2009, and shortly thereafter, we began to see more aggressive deals on refurbished iPhone 3G models. However, it wasn't until nine months later that we saw the 8GB iPhone 3G finally hit rock-bottom at $0. Prediction for the Upcoming Cycle: In other words, when the much-rumored iPhone 5 is released, it will still be awhile before an iPhone 4 refurb hits $0. In fact, we predict it won't be until halfway through the new iPhone's life cycle. Conclusion Although you can generally find excellent smartphone deals weeks after a phone's release, it takes at least two months for some phones to reach the $0 mark. Retailers to keep an eye on are WireFly, LetsTalk, and Amazon Wireless. Unfortunately, Apple fans won't find many deals on new iPhones. Instead we recommend keeping a vigilant eye on Apple's clearance/refurb section or when new iPhone announcements are made, since this means previous models will see significant discounts. (AT&T Wireless has also offered large discounts on refurbs.) You can also set up an email alert to know immediately when we list your favorite smartphone for free. All smartphone deals mentioned in this story require a minimum 2-year contract and/or data plan. All items mentioned are available at the lowest total price we could find from a reputable seller at the time the story was published. An avid gadget lover, Louis Ramirez has covered technology for Gizmodo, CNET, Laptop, and various other publications. Follow him on Twitter at @LouisRamirez. You can also sign up for an email alert for all dealnews features. DealNews may be compensated by companies mentioned in this article. Please note that, although prices sometimes fluctuate or expire unexpectedly, all products and deals mentioned in this feature were available at the lowest total price we could find at the time of publication (unless otherwise specified).