[Quian]

Forum link in reference for this is:
https://comicbookplus.com/forum/index.php/topic,7630.msg51567.html#msg51567
(by crashryan)

The following link is to a vid-clip that makes connection to the Submarine play structure sold in comic adverts.
CSI: Cardboard Submarine Immersed
( CSI:NY segment from "The Sit Down" )
http://www.dograt.com/2008/06/20/csi-cardboard-submarine-immersed/
{ *** You will not be amused by this clip. *** }

Yes, I know they used a modified prop for the tv show. But they do make reference to an actual comic advert. Even though it was updated for their use. It does make one wonder is any kids in real life, did ever try to make one float.
On another note. Regarding the tank version. If you are interested in a Sherman Tank mini (scaled down). Here is a link to a 17mb rar (includes 2 PDFs & 2 short videos), of a working metal kid's tank.
http://www.mediafire.com/download/dmd4b7cgxjushh0/Sherman_Tank_mini_(scaled_down).rar

If you viewed either item linked above. What did you think of it (or them)?

[josemas]

I had some friends, as a kid, who ordered the submarine.  It was, indeed, just made of cardboard.  They still decided to launch it into a swimming pool where it proceeded to sink and turn into a pile of paper mush.

It was seeing my friends getting ripped off time after time that kept me from ordering much of those items being advertised no matter how tantilizing they might look in the ads. 
I did order the miniature "spy camera" which did take pictures, albeit somewhat fuzzy ones.  I never did get any additional film for it.

Best

Joe

[narfstar]

I wonder if too many people wised up or the comic audience got older that caused them to go out of business.

[paw broon]

Quian, I'll get around to your links but I'm on my tablet right now and not o lot of charge left.
There are some examples of the sort of rubbish British kids were tempted with on the back pages of some comics onCB+ and here's one
comicbookplus.com/?dlid=29133
I'm trying to find the x-ray spex 'cos everyone wanted a pair and you'll never guess, they were rubbish!
Here's another, this time on the inside back page
comicbookplus.com/?dlid=33828

[crashryan]

To narf's question: I believe the junkshop ads were already gone before comics readership moved into the college-age-and-older range. My guess is that total circulation went way down (meaning fewer customers) at the same time production costs, represented by rising cover prices climbed quickly (meaning higher advertising rates). The profit margin on those cheap products had to be pretty slim. I'm guessing the sellers just got squeezed out.