You'll only buy when the choice is simpler. They learn this at salesperson training school. When choosing a link rather than parting with money, we can cope with more choices than two, but there's still a limit. Somewhere in the muddled area between mathematics, sociology and cognitive studies there's a theory about the way we perceive numbers. It says the fact that we have ten fingers is a big deal.
Sign language is probably the origin of base ten mathematics.
Our minds find numbers up to ten straightforward, after that we're dealing with complexity. It might be nonsense but most two year olds would probably agree with it. On this basis it's probably wise not to offer choices in blocks of more than ten. Eight would be preferable, five even better, but if you have to push the limit then it's probably ten. Many search engines return results in blocks of ten.