Introducing Scooby Snacks!

I had a lot of time to think this past weekend and got to thinking about my contests.

Sure, it's cool to host, and giving is always the reward to me, but what if this
particular prize that I'm offering for the contest is something that the winner
doesn't collect? How can I go about giving them something that they do collect?

I know! I'll give away Scooby Snacks!

That way I can just keep throwing out puzzles, people can fill their dog bowls
with Scooby Snacks, and maybe once every 3 months offer up a wide selection of
items for people to redeem their Snacks on!

By now you probably realize that I like to host puzzles and games to exercise those
brains. So, in the future (yes, even Mastermind), I will offer up Scooby Snacks as
the prizes. The number of Snacks you receive will depend on the difficuly of the problem
or puzzle at hand.

I will run this first "earning" period up until the beginning of December.
Try to collect as many Scooby Snacks as you can between now and then and I will
allow redeeming of the Snacks around then in time to ship for Christmas! You may
redeem them at that time or you may choose to continue to save them and use much later
for a better prize! They will not expire!

I will offer up a wide spectrum of things to choose from. From CCF coffee mugs or sponsorships
(pending approval from Dad) to mint sets, to silver lots, to world coins, to who knows!
I will put up whatever is in my current inventory at the time. If you don't see something you
want, you can just bank them for the next redemption period!

The only thing I see so far as being a "potential" problem is that if I only have one
item that more than one person wants. The only way I can see a disclaimer is that it
is first come, first served. Just like if you walked into any store to buy an item and someone
just before you bought the last one. Well, there aren't anymore. But, we'll cross that bridge
when we come to it.

DO NOT go back and edit your post. If you want to change the answer, just repost. Edited posts will not be counted!

Only the first correct answer will the earn the Scooby Snack(s).

Sometimes you will need to explain your answer. If I don't feel you've answered to my satisfaction, I may not reward you with the Snack, even if the answer is right. I want to be sure you have worked the puzzle out and how you got to the answer, rather than just googling it.

Feel free to throw out any questions or suggestions!

Over the course of the next couple of weeks, I am going to throw up some puzzles of varying difficulty.

Ready?

For the first ever Scooby Snack:

Three men want to cross a river. Not having a boat, they approach two boys who had one and offered to pay them
for taking them across. The boat could only hold 150 lbs safely. Each of the boys weigh 75 lbs. Each of the men
weigh 150 lbs. They agree to pay the boys $1 for each time the boat crosses the river. The boys agree as long as
they end up right back where they started.

What is the least amount of money that the men can spend to get across the river and leave the boys where they started?