Put simply, most of the time, the difference between bundle hair and packaged hair for the beauty supply store is the quality. When buying bundles, you are generally looking for 100% virgin remy hair, great quality that lasts a long time.
This is not to say that you can't get quality hair at a hair store, you can. This will likely be the hair behind the counter.
For those who don't go there often, this can be very overwhelming. There are tons of brands, but just know that quality hair will last you a long time.
Many times with packaged hair, the hairs on the weft come from many donors with many different types of hair and not much care is taken to ensure the hairs are the same length or lay in the same direction. When the hairs are not the same length or placed in the direction of growth (remy) it leads to matting, shedding and tangling.
Our hair extension bundles are 100% virgin (never chemically treated) human hair. We set quality standards to ensure each bundle is perfectly full and soft. Hair comes in many textures, densities, and porosities and we feel it's important to have hair that looks and feels like your own.