Email marketing, although a proven and required part of a marketing strategy, can be costly with most online suppliers charging a hefty monthly sum to use their systems.
Those that operate for free have limitations, usually something like '100 recipients only' which is ok for low level activity but unsuitable for a growing business.
Setting up your own system e.g. using something like PHPList is often tedious and takes some technical knowledge to set up properly and working just right.