Optimus Prime is one of the most popular and highly rated buildable models in the Lego Icons lineup--for good reason, too. The 1,508-piece collectible display set has an exceedingly clever 2-in-1 design that allows Transformers fans to convert the Autobot leader into his signature truck. Ahead of Prime Day 2025, multiple major retailers have restocked the 1,508-piece Optimus Prime set for $144, which is a 20% discount from its $180 MSRP. At the time of writing, Amazon is running low on units, but you can also snag this deal at Walmart and Target.Lego Icons: Optimus Prime Transformers 2-in-1 Display ModelAll three retailers have sold out of this display model, which is geared toward adults, several times already this year. And though it has returned once again, it's worth noting that Optimus Prime was out of stock everywhere from last holiday season until March. The Lego Store has units available at the moment, but it'll cost you the full $180 MSRP. Lego officially lists Optimus Prime as "hard to find." This description combined with the prolonged stock shortages could mean that the Optimus Prime kit, which debuted in 2022, is close to retirement.Amazon also has great deals on two other iconic vehicles from movie history. The Lego Icons Back to the Future Time Machine is discounted to $170 (was $200). This is a 3-in-1 build, but unlike the Transformers sets, you'll need to pick which DeLorean model from the trilogy you want to build. If you change your mind later on, you can partially deconstruct the model and rebuild it using the instructions for one of the other designs. Similar deals are also available at Walmart and Target.Meanwhile, Dune fans can save 20% on the Lego Icons: Atreides Royal Ornithopter, dropping the price from $165 to $132. The 1,369-piece build comes with six Lego minifigures.Check out a list of our favorite Lego display model deals for adults below:Lego Deals at Amazon (July 2025)Lego Icons: Transformers Optimus Prime 2-in-1 (1,508 pieces) -- $144 ($180) Also at Walmart (Sold out)Also at TargetLego Icons: Back to the Future Time Machine (1,872 pieces) -- $170 ($200) Also at WalmartAlso at TargetLego Super Mario: Piranha Plant (540 pieces) -- $48 ($60)Lego Ideas: Sonic the Hedgehog - Green Hill Zone (1,125 pieces) -- $73 ($80)Lego Marvel: Infinity Gauntlet (590 pieces) -- $63 ($80)Lego Technic: Peugeot 9X8 Hypercar (1,775 pieces) -- $173.85 ($200)Lego Architecture Landmarks: Himeji Castle (2,125 pieces) -- $136 ($160)Lego Architecture: New York City (598 pieces) -- $46 ($60)Lego Icons: Tranquil Garden (1,363 pieces) -- $88 ($110)Lego Icons: Bonsai Tree (878 pieces) -- $40 ($50)Lego Art: Vincent Van Gogh - The Starry Night (2,316 pieces) -- $138 ($170)Lego Art: Hokusai The Great Wave (1,810 pieces) -- $85 ($100)Star Wars Lego DealsStar Wars fans should take a look at the Walmart-exclusive Kylo Ren and Darth Vader Helmet bundle while it's in stock. Over at Amazon, you can save on a nice variety of 25th Anniversary Lego Star Wars sets, including the 1,138-piece C-3PO statue. For even more offers, check out our. roundup of the best Lego Star Wars deals available now.Lego Star Wars 25th Anniversary Series:Millennium Falcon (921 pieces) -- $68 ($85)C-3PO Droid (1,138 pieces) -- $112 ($140)R2-D2 Droid (1,050 pieces) -- $80 ($100)Droideka Destroyer Droid (583 pieces) -- $52 ($65)Mos Espa Podrace Diorama (718 pieces) -- $54 ($80)Tantive IV Starship (654 pieces) -- $64 ($80)Boarding the Tantive IV (502 pieces) -- $46 ($55)Lego Star Wars Helmets:Darth Vader + Kylo Ren Helmet Bundle -- $99 ($134)Darth Vader Helmet (834 pieces) -- $64 ($80)The Mandalorian Helmet (584 pieces) -- $56 ($70)Captain Rex Helmet (854 pieces) -- $56 ($70)More Starship Display Models:Acclamator-Class Assault Ship (450 pieces) -- $40 ($50)Home One Starcruiser (559 pieces) -- $56 ($70)