Best Fiber Underlayment for Flooring

My brother in law worked in home construction for maybe 20 years, before he decided that he was getting too old for it and found a different career. But he still has a lot of the skills, and so I am going to use his expertise to help me do some DIY projects at my house without having to hire any contractors for the work. I should stand to save a lot this way and I am going to try to purchase some fiber underlayment to use to put under some new flooring we are going to put in the house.

I was at a hardware store and they did not have the type of underlayment that my brother in law recommended we use, and so I decided I would probably have better luck trying to order it off of the internet. At least, that way I know I can find a place that has it, and hopefully I will also be able to find it for a good price. My only concern is how much I am going to have to pay for shipping, which could be quite substantial, but I am not really sure just yet. I should try to see if there is anywhere within a 20 mile driving radius that has it for a better price than what I can buy on the internet.

I would probably be willing to spend more to order it online, rather than driving to pick up at the far edge of the radius I quoted above. Just because it would be kind of a hassle to have to drive that far to pick something up, and I would prefer to just order it online if the price is relatively similar. Anyway, I won’t find out what prices are until I actually start looking.