I bet it did cost them but I think it was a pretty good move on their part. Really... does it cost 1 dollar to make a hook? Of course not. Probably cost them a dollar or so for every pack of hooks they sent out for free.
For sake of argument... say it was 10,000 packs sent out. OK... $10,000 initial investment.
(Don't have a calculator available so this is all done in my head so bear with me if I make a mistake)
Say only a third of the people receiving these hooks begin to buy Trokar and buy one pack to try them again. Trokar profits $3.00 per pack. So... you are back to almost your initial investment with $9,900.00.
These same 1/3rd will buy more (Really...how many times do you just buy one pack of hooks?) and say it is just 3 more packs. We are at 9900 packs at $3.00 profit for a total of $29,700.00
Now... there is a return on the investment by Trokar. This will compound based on word of mouth.
Add that to say... they average only one person by word of mouth that buys 1 pack based on their recommendation... add another $9,900.00.
Total profit = $39,500.00.
Even if you factor in two packs per person sent... still a profit of almost 29 grand. Since Trokar is owned by one of the biggest fishing manufacturers in the world, Eagle Claw, there is nothing lost here by them. More than likely it was 100,000 people who responded so profit would be more like a quarter million bucks.
I do not know how many packs of hooks they sent out or what their profit margin is but you can bet... they though this out. Anyway... it's probably from the advertising budget and any loss is tax deductible.