CAN I USE RED WINE VINEGAR INSTEAD OF REAL RED WINE?

Basically no. It depends on how much acidity the dish requires and how much red wine is required. Half a cup of red wine vinegar has a lot more acidity than red wine. Anyway a bottle of cheap red wine doesn't cost too much so where is the problem! You can always drink what you dont need or just keep it untill you need to cook with again.