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LEGO has quietly added another September 2026 gift-with-purchase to the US offers page, and this one is a broad promotion rather than a theme-locked exclusive. LEGO 40780 Birthday Cake is now listed as a new US GWP for LEGO Insiders, running from September 9, 2026 to September 19, 2026 while supplies last. The official terms confirm a $65 minimum spend on LEGO merchandise, plus an Approximate Retail Value of $12.99. That combination matters because it makes 40780 a lower entry-point freebie than some recent US promos, and because it is not restricted to one narrow subtheme. If you were already planning an order, this is the key new promotion now live on LEGO.com in the US.
The official LEGO offers page, the LEGO 40780 Birthday Cake product page and the current LEGO offers terms page now line up on the same promotion. That is usually the point where a GWP is fully live rather than just briefly exposed in one corner of the site.
LEGO 40780 Birthday Cake US GWP key details
Here are the headline facts confirmed by LEGO:
- Promotion: LEGO 40780 Birthday Cake
- Availability window: September 9, 2026 to September 19, 2026
- Region: United States
- Channel: Online at LEGO.com
- Eligibility: LEGO Insiders members only
- Minimum spend: $65 in LEGO merchandise only
- Approximate Retail Value / ARV: $12.99
- Limit: One per household, while supplies last
The most important practical point is the threshold. Unlike theme-specific promotions that force you into one license or category, this one is described by LEGO as requiring a purchase of at least $65 in LEGO merchandise only. That reads as a wider and simpler qualification route for US buyers, though the official terms still exclude Pick a Brick Standard orders.
What LEGO 40780 Birthday Cake is
LEGO lists 40780 as a 160-piece set aimed at builders aged 7+. The product page describes it as a buildable pretend birthday cake with a small play scene hidden inside. Official product copy also points to chocolate icing, colorful sprinkles and decorative topper details, while the inside reveals a minifigure setup with accessories including a table, a present and a flame element for the cake.
That makes this GWP feel closer to a compact celebration display piece than a generic filler polybag. It is clearly designed around birthday gifting, but it also looks broad enough to work as a seasonal freebie for anyone placing a September order rather than only fans of one single theme.
Why this new GWP stands out
There are three reasons this promotion is worth flagging. First, it is genuinely new on the US offers page. Second, it comes with a relatively straightforward $65 spend requirement. Third, LEGO has given it a clearly stated $12.99 ARV, which helps readers judge the value proposition more easily than with some past freebies where the set value was less visible in the promo copy.
It is also notable that LEGO is running this alongside the already live Batman: Bruce Wayne and the Batsuit 30726 promotion. That matters because some shoppers will now be looking at whether a single order can line up with more than one offer, or whether they would rather aim for the broader 40780 threshold instead. As always, the exact stacking behavior depends on LEGO’s live cart logic and stock position at checkout, so the safest reference remains LEGO’s own cart and terms page.
Official terms to watch before ordering
The terms page confirms the standard limitations LEGO fans will expect: while supplies last, one set per household, no retroactive application to previous purchases, and return rules that require the free item to be returned if the qualifying purchase is refunded. LEGO also states that the promotion is not valid at LEGOLAND Parks, LEGOLAND Discovery Centers, or LEGO Certified Stores.
The wording also specifically says LEGO Insiders membership required. So while the threshold itself is broad, this is not an everybody-gets-it promo. You need to be signed in as an Insiders member when placing the order online.
Minimum spend and value snapshot
- Start date: September 9, 2026
- End date: September 19, 2026
- Minimum spend threshold: $65
- Gift value / ARV: $12.99
Final takeaway
LEGO 40780 Birthday Cake is now officially live as a new US gift-with-purchase for LEGO Insiders, and the promotion window is already running. If you are planning an order anyway, the key numbers are simple: September 9 to September 19, 2026, $65 minimum spend, and a stated $12.99 ARV. That makes it one of the clearest current US LEGO promos to evaluate at a glance.
As usual, stock can disappear before the end date, so the real deadline is whichever comes first: the published cutoff or LEGO running out. If LEGO changes the wording or expands the promotion conditions, we will update from the official source pages.
