Is there a phrase or word to describe when you sell something small in order to establish a business relationship, build confidence and establish a market/infrastructure in order to sell consumables, service, other products or similar later on?
Bait-and-switch is wrong because what is being advertised is what is being sold, at the advertised price and there is no requirement for further purchase but its main purpose is to increase other sales. Selling razors or ink jet printers cheap in order to make money off razor blades and ink cartridges later on are typical examples.
EDIT: A slightly better example might be an auto manufacturer, since razors don't come in very different price steps. Suppose Honda pushes in a developing country to win a cyclist over to using a moped. Once they have made the step to using a motorized vehicle, they have established a relationship with the customer and they grow accustomed to it. From there, they can sell consumables for the moped and a new one once the first wears out but furthermore a motorcycle or even a car at a higher price. The initial moped was a real product and not sold at a loss, buy they have a grander scheme of offering an entry level product to the market.