Since Crypto-currencies can be traded down to 8 decimal places (with todays 'Core' software, though the it can be increased at any time if necessary), it would be fair to say that Bitcoin et al, will always be within reach of the average buyer. Unlike a single unit of Apple stock for instance, most bitcoin units are already traded in small fractions. There is a mental hurdle to get over however, as most of my friends still want at least 1 whole unit, before they feel they own any.