Get home directory by username

You can use eval:

eval echo ~$USER

But see Andrew's comment and glenn's reply below.

This might work for you:

homedir=$( getent passwd "$USER" | cut -d: -f6 )

This will also work on users that are not you. For instance,

homedir=$( getent passwd "someotheruser" | cut -d: -f6 )

It seems you are that user -- why not

echo $HOME

?