The 'post-scarcity age is an anticipated period where due to advancing technology and efficient use of natural resources there will be a great abundance of material items that people require, with a minimal impact on the environment.
When society reaches this point, everything from basics like clean water, nutritious food, medicine and housing to less essential material goods like vehicles, computers, mobile phones and all the way up to purely luxury goods, will be available 'on tap'.
Abundance of the fundemental resources
Despite the impression given today, the basic resources for any civilization - energy, material and intelligence - are not in short supply in the slightest, in fact we would be very hard pressed to make even the slightest dent in terms of 'using up' the avaiable capacity.
It is simply the current inefficient and wasteful methods, and economic restrictions that make it appear that there are critical limitations of these resources.