Fare from Mexico via America included in high cost (5)
I believe the answer is:
tacos
'fare from mexico via' is the definition.
I can't tell whether this definition defines the answer.
'america included in high cost' is the wordplay.
'america' becomes 'a' (common abbreviation - e.g. in organisation names).
'included in' indicates putting letters inside.
'high' indicates an anagram (can mean drunk or on drugs and hence disordered).
'cost' anagrammed gives 'tcos'.
'a' inserted inside 'tcos' is 'TACOS'.
Can you help me to learn more?
(Other definitions for tacos that I've seen before include "Mexican tortillas with various fillings" , "Foreign dish" , "Snacks" , "Mexican food" , "pancakes" .)