Description: As the name indicates, it's just a bar with no seats or stools.
System: Standing bars are more likely to be Western-style, which is to say you will order then pay at the bar. Despite the fact that there are no seats, you could be told the bar is full when all of the counter space is only one deep.
Budget: Standing bars can be bargain basement--300 yen per drink--or if they're aimed at expats they could charge regular bar prices. The deciding factor here will be the location and the crowd that shows up.
Making friends: Usually allowed.