Samples can really save the day. I don't mean for amount of product but for free or to pay a small amount they are a great size to determine whether or not they are worth the money. Let me give you an example - the Kiehl's Midnight Recovery Concentrate is £36 full price for a facial oil that should 'fix' your skin. It has been raved about in the blogging community and as a recent graduate with no employment as of yet, I really cannot afford to spend £36 on a facial oil when I didn't even know I would 'need' it. Besides the point that I didn't love it to be honest and much prefer a serum. That is then £36 not wasted because the sample was free.
Here's another example. Benefit released Puff Off £22.50 and they sent me a little sample to see how I liked it. I was so glad I could try it as there is also no way that I could afford that to see if the product reduced my puffy eyes in the morning for that price when there is a big chance in fact that it might not have made a difference. Luckily enough I did enjoy the product but as I already own It's Potent £25.50 by Benefit there was not much point me spending extra money when I was happy with the two large pots of them.
This goes for Mac's Prep + Prime £21 and I received this sample a while ago. I actually quite like the product but still have a lot of Benefit's Porefessional £24.50 full size left. Once I have ran out of that then Prep + Prime will be on my 'to buy' list but I'm glad I tried a sample out first. This can relate to a lot of products to be honest especially with high end products where you don't want your money wasted.
As much as I wish I had the money to buy a product as soon as I could see it, it really can be a waste of money. With skincare and foundations you do need to try them before you buy them. The money not spent on them can go towards a product you know you'll love e.g. an eyeshadow palette by a brand you trust to make quality products. If you can get your hands on a sample you're eager to try then take the opportunity.