Good idea, is there any activation fee for these cards? Can you get the exact amount that you will need? like $175.46?
At the CVS I was at I only saw a $50 gift card for BB but they had Amazon ones that were like $25, $50, $100 and one that would let you specify an amount up to around $200. So I'm not sure if BB has something similar.
I don't believe there is an activation fee for the BB gift card either, the only ones with fees are probably the credit card ones for visa, amex etc. I'd give it a proper read first though as I didn't look too closely at the BB ones.