Understand the difference between a knock-off and a genuine bag
Knowing the difference enables you to make an informed choice about the purchase of any bag.
A genuine designer bag is made by the original well-known designer; it can also be made by a less-known designer but the main focus is on high-end designers. The bag's logo, attachments, etc., are all part of the original design down to the exact positioning and number of such features. Tags, signatures or marks stating the designer's name form an integral part of the bag's overall design and authenticity. Price is determined by what the consumer is prepared to pay for a designer label.
A legal knock-off/imitation is "designer-inspired" but not a direct copy. Provided such a bag does not claim to be the original designer's bag and does not attempt to use the trademarked symbols,or features. In most cases, it can legally imitate the style and colors of an authentic designer bag while taking care of any defining features deviate in evident ways in order to avoid. Although it may suggest the bag's similarities to the brand that it's inspired by, it won't claim to be an actual designer bag. Without close inspection, the additions can be easily mistaken for the real thing, sometimes causing you to spend too much on it in the belief of the original designer's bag. However, if you know what to look for, you should be able to spot the differences.
Illegal, fake bags put themselves across as being the genuine designer's bag, right down to the very last logo, tag, charms, etc. Fakes copy everything about the designer bag, and pass themselves off as the original brand with no attempt to distinguish themselves as look-alikes. Prices for fakes can vary considerably from cheap to trying to sell the bag for high amounts. It is illegal to make fake merchandise, and while buying it, doing so supports illegal activity.
Usually the store will proudly say something along the lines of "as licensed by X brand for our store".