Not that we buy LEGO as an investment - that would involve us actually selling it at one point. Maybe when we're 70 somethings but I predict I'll still hear the boy yelling in the background, "Don't sell my LEGO!" But for a toy, it sure does seem to hold its value.
Take for instance, the Ultimate Collectors Series Imperial Star Destroyer. This thing is huuuge - that's a 4 person table it's dwarfing. Originally released in 2002 with a MSRP of US$270, it now routinely sells used for around $500-$700.
Sometimes, if you leave it alone while you're building it, some whackadoodle will come along and cover it with flowers. I happen to think it increases the value but apparently, I'm in the minority.
And then there's the crown jewel of our collection: the Ultimate Collectors Series Millennium Falcon. Released in 2007 for a whopping $500 (to date, the most expensive retail LEGO set), it now sells for over $1200 used.
But they don't have to be gigantic or Star Wars to skyrocket in value. The first of the Modular buildings was the Cafe Corner - it's the building on the far left.
Also released in 2007 for $140, the completed sales for this set hovers between $600-800 used. It's adorable and this theme is among my favorites.
Not all sets appreciate this quickly and sharply. Luckily, we don't really consider the aftermarket when we buy ours.
If you have some LEGO lying around your house that your kids have outgrown, it will probably not be collector grade. Imagine! Children playing with toys? Perish the thought!! *grin* BUT you'll still be able to get anywhere from $4-7/lb provided it's in decent condition.
I gave some advice to a friend who was trying to sell his 45 lb tub of LEGO. He originally thought about selling it for $50. After chastising him, I told him what to take photos of, asked him a few questions about the different sets/themes and wrote the ad for him. He ended up accepting $300 for the lot and could have gotten more but I think he just wanted it out of the house. I would have bought it myself but alas, the shipping charges would have been too high.
In return, he sent me 2 minifigures as a thank you which was awesome! Yup, that's me. Will work for minifigures.