Yes it should be fine. However, if you are using water conditioner then there's no reason to age the water. Water can be added straight from the source (sink), unless you have to alter the water chemistry before you add it to the show tank, in which case you would most likely be using a holding tank and a pump to transfer the water (for larger applications).
As for the OP's problem - order it online. Amazon has seachem prime for cheaper than any store to which you could go, and it will show up at your doorstep. The 500 ml bottle (treats 5,000 gallons) costs $12 (nearly 50% off). Spend another $13 and you'll get free shipping.