Is Trader Joe's inexpensive?
Price perception is an emotional topic for consumers .. and one that retailers approach with scientific thought. There is never a simple answer to the question "is retailer X inexpensive?" in a highly competitive industry such as retail, especially grocery retail. Every grocery retailer (including the oft criticized Whole Foods) strives to get their customers thinking that they offer the best value!
Retailers invest to understand what draws shoppers in - price, quality, availability, exclusivity, freshness, etc. If being low on price is the driving factor, analyses tells them which products they need to be competitively priced on and by how much. They also know which products they don't need to be competitively priced (usually the candy in the aisles as you walk up to the register) that they can harvest margins on.
Trader Joe's has adopted interesting strategies: primarily promote private label products - as in, there are very few products that you see at a Trader Joe's that you can buy elsewhere .. makes it hard to compare & tell if they are more or less expensive. In buying fruits & vegetables, they price differently and offer the convenience of knowing what each piece of fruit is going to cost (as opposed to paying by weight at other retailers) - while knowing what your final bill is going to be is comforting while filling your basket, there is a pretty good chance that your fruits are more expensive than elsewhere. Their strategies offer value to the young, small families who care more about convenience and less about the pennies. The private label strategy allows them to bring some interesting products, some of which are interesting, potentially of better quality than your typical grocer.
Unfortunately, as a consumer, it's impossible to shop multiple retailers and is harder still to know what is less expensive where - so, we tend to stick to the one that's closest, or appears to offer the best value, based on our perception, that retailers carefully cultivate with the help of big data & analytics.
PS: I am a big data analytics professional & help retailers with price optimization - I am also a consumer; I am fascinated by how retailers are evolving in this hyper competitive modern world. Its important to recognize that retailers are running a business and need to profit. In the long run, if retailers continue to be focused on margins and drive customers away, they will cease to exist. Through my profession, I believe we help retailers strike the balance between offering best value to customers and staying more than solvent.