Your question is very open-ended.
What is the intended purpose for the bag? A casual carry-around-town bag is going to have different features (and size, and weight, and cost) than a carry-to-the-airport bag.
When you say 'fit your bindings' do you want the bag to fit the board with the bindings still attached to the snowboard, or loose in a pocket/compartment?
Do you want the bag to have a shoulder strap? Backpack straps? regular handles? Padding?
It would be best if you gave a description for how you plan to use a bag.