I didn't know you had Amazon gift cards on you. That makes a little more sense, I suppose. I'd want to milk it for all it's worth too.
However, I'd still say that, if you can't find what you're looking for on Amazon, go with Retrogression and/or other online options. Time spent waiting for parts is time you could potentially be spending riding your bike.
And money spent on gas / fare hopping from local shop to local shop is money you could spend on better parts.