Pricing models vs. the internet

I recently purchased toner for my printer. At a shop near my house, the cartridge cost $85 plus tax. I found an online store selling compatible cartridges from different manufacturers for between $25 and $200 including tax and shipping. Meanwhile, the printer itself cost $100 new (including taxes, shipping, and a toner cartridge).

I also need a new pair of glasses, to replace the ones I’ve worn for about 12 years now. I visited a few stores in town, which each had a few hundred pairs to choose from, for prices ranging from $200 to $300. I’d like to buy glasses in person, and have an experienced salesperson help find frames that fit me, so I asked if I could see a catalogue from their distributor in order to see more options, but was told that wasn’t possible. So I looked online, and found two pairs I thought I’d like: after taxes and shipping one cost about $230, and the other cost $33. I ordered the cheaper pair, and if I don’t like them will go with the more expensive company, who are willing to mail me the frames without lenses for me to try on before I have to commit to buying them.

One more story: when I need a small cable or adaptor, I usually buy it from an online store in Hong Kong that sells these parts for $1-$2 and doesn’t charge for shipping. I’m guessing that assuming the mailing costs serves as a loss leader for them and encourages customers to make larger and more frequent purchases, but their prices on more expensive items are generally higher than what I’ve found elsewhere so I don’t understand how their business model could be working.

It continues to amaze me that so many wildly divergent prices are being offered simultaneously. How are all these corner opticians in my city still in business when you can generally get exactly the same frames online for half the price? (For that matter, why are there so many currency exchange shops downtown given that banks offer much better rates when you just use your credit card or bank card at their ATM?) Surely this can’t last forever.

PS: Yes, I know that cheap online shopping means horrible working conditions in North American warehouses, not to mention the actual manufacturing facilities in the Pearl River delta. I would be very happy to pay a small premium to a company that treated their workers better, much like I do for coffee. I don’t know of anyone attempting to meet this market demand, however.