$ mean that you'll test hexadecimal value

$0f = decimal 15 = 00001111 binary

binary %
Hexadecimal $

Conventional 'AND' is use for condition statements like IF

IF (PORTB=$FF) AND (PORTA.1=1) then


Bitwise AND '&' is to process logical stuff

Let's say PORTB= $F3

Myvar = PORTB & $0F

Result of MyVar will be $03