That makes it quite expensive. Much cheaper to buy a year's worth. However R50 is not bad if it's a month with good free games. So you actually have a point there.
Longer term its more expensive but if you on the fence, its a good way to see if it's worth it.
Just remember to remove the recurring payment which is on by default.
I'm open to correction but XB1 games with gold only work if you have an active gold membership ?