When you are at a conference or place that gives away freebies, DON'T TAKE THEM unless you will really use them and they will save you money.
IF you will use a free sample of detergent or shampoo, you can take them on a trip as a carry on if the sizes are within the guidelines. BUT, if you just get them because they are free and don't use them, you are just cluttering up your home.
If someone is handing out free candy and you will really eat it, then enjoy it. But, if you aren't going to eat it and it will end up getting thrown in the garbage, just don't take it.
A few years back, I decided to try couponing. I got lots of stuff for pennies on the dollar, and got lots of sample sizes for free. One of the problems with this is that people in our family found that they prefer a certain deodorant or shampoo over the others after trying several. So, cheap or free, it wasn't worth it to get whatever I could find if no one would use it. But, if you aren't picky about what you use, it is a great way to save money. It all depends on what you will do with it. If you plan on going on a trip, having some sample sizes of things is nice. It isn't eco-friendly, but it is convenient.
Depending on what you like and don't like, don't take the freebies UNLESS you will really use them.