Anonymous
Buy maybe a box of 50 snack-pieces of candy.
In an apartment, usually there are security doors and kids don't come into the building for trick-or-treating.
Usually they go ONLY to houses, and the signal that the house is giving out candy is when the front porch lights are on ... and some sort of Halloween decorations and/or a jack-o-lantern is put out.
In an apartment ... most likely you will not have any kids. You will know after your first Halloween in that apartment.
Make sure you buy a candy you like, in case no one comes and you have to eat it. OR donate the candy to a teen runaway shelter or a children's hospital if you don't want to eat it yourself.
Joe
Nobody trick or treats in an apartment complex, so don't worry about buying candy.
Chiralty
You'd best buy some candy! chances are some kids will show up
MELONS
buy what its easier