I just did a price comparison with Scottish Opera's production for next Friday (29 Jan 2016), a premiere of a new work ("The Devil Inside", words by Louise Welsh and music by Stuart MacRae) and the Celtic Connections event at the most comparable venue, the "Transatlantic Sessions".

Scottish Opera: 16 pounds to 30.50 pounds.
Celtic Connections: 27 pounds to 30 pounds.

A fairly basic ticket to see Rangers v Falkirk the next day costs 20 pounds. I presume it would be a lot more to watch Rangers losing to a team anybody had heard of.