While you don't necessarily have to write a procedure to contain this logic, doing so in a scenario like this often helps make your template easier to understand. It may also make the wikitext easier to debug if you mess something up.

A call-type procedure can look like this:

\procedure call-type()
  <$let areaCode={{{ [<currentTiddler>split[]first[3]join[]] }}}>
    <% if [{CurrentAreaCode}match<areaCode>] %>
      local
    <% elseif [enlist{TollFreeAreaCodes}match<areaCode>] %>
      toll-free
    <% else %>
      long-distance
    <% endif %>
  </$let>
\end

The TollFreeAreaCodes tiddler will contain 800 888 877 (or any ordering of those three space-separated numbers, or those numbers each surrounded with square brackets, like [[800]]), and the CurrentAreaCode tiddler will contain 212. Then just drop something like this in an appropriate spot in the template:

Call will be <<call-type>>.