Hi Jim,
The use of
vos (known as
el voseo) is indeed very popular in Costa Rica. Here is a
link that'll help you solidify its use (the Ticos use the 'General' form).
You'll read that
vos is the singular form of the second person (not the plural), and that it replaces
tú, also the singular form of the second person.
The plural form is
ustedes (for both the second- and third-person form of 'you'), just like everywhere else in Latin America. In those countries, no one uses the second-person plural
vosotros.
You'll also see that
querés is the correct spelling of 'you want'. The spelling you provided is the one used for
vosotros, and it is pronounced different.
¡Divertite!