The cheapest tickets for an Avalanche game are typically found in balcony sections behind the net. If you have a choice of which end to sit on, highly consider the type of experience you're looking for.
If you're bringing family and are expecting frequent trips to restrooms or concessions, consider sections on the west end of the arena (317-331). You'll find a number of facilities and food stands on this end of the ice, while there are virtually none on the other end.
So why sit on the east end? If you're an Avs fan this will give you the best look at their scoring chance. The Avs shoot towards the east end in the first and third periods, making these seats more sought-after among Colorado fans. Just make sure you grab your snack and head to the restroom before getting to your seats.
Like balcony seating in other areas of the stadium, odd-number sections occupy the first three rows of the upper level. A set of stairs then leads to the even-number sections where row 6 is typically the first row up from the stairs.