To me this is the most pushing issue.
I have created a new puzzle, which I have not yet revealed to everyone.
The construction of a single one of those puzzles + stickering have cost around $50-60 for my first prototype. And I think, using the same method. I could keep my production cost as low as $50. But that's still too expensive to sell to anyone else if you count shipping and profit to it.

I would gladly appreciate tips and tricks to reduce the cost of my puzzle!

Shell it to .7 to .9 mm and put holes on sides that aren't visible if it doesn't affect turn quality. Other then that get the density discount and order a few of your puzzles in a single model so they cost a lot less individually.

Well, It was a hand made puzzle, so I haven't made a 3D model yet.

Any ideas on reducing costs of hand made puzzles?

If you aren't 3D printing it, then we'll need to know what methods/materials you used when handmaking if can be of any help.

Well, I actually buy several premade twisty puzzles. Then cut what I need to cut a handsaw and do the rest of the modding with glue and fine to coarse sandpaper.

The puzzle weighs in at 250 grams. Would that be relevant in printing? If so, how much do you think it would cost to print?

Volume of material is the only factor for 3d printing price. Almost always it is more expensive then hand modding.

$50-$60 sounds like an extremely reasonable amount for a handmade puzzle.

that's disappointing
How about casting, would that make for a cheaper price than my way? (buying puzzles to cut down and re-use the parts for my own puzzle). It has 6 different kinds of pieces. But I could use the core of one bought puzzle and then cast 3 different pieces to complete my puzzle.

Would casting be cost-effective or as much counterproductive as 3D-printing would be in terms of cost reduction?

All of these questions would be easier to answer if you showed us the puzzles.

I would agree with Ben. Handmade puzzles can easily sell for $100+, obviously depending on the craftsmanship and the puzzle itself. What I would recommend you do is make the puzzle, show it to us, and then either sell it through eBay, or if you're not satisfied with it or you think you can make a cheaper version, keep that puzzle for yourself and produce another one.