Most fish stores...(not chain ones, like petco or petsmart) will order fish for you.
If there is something you want let them know.
OR
You will have to buy online.
Look for an online fish seller that is relatively close to you because you will have to pay for fast shipping.
I live in california...
Things to consider...
Is the water heated?
Is there filtration?
Goldfish/koi do not need very warm water, so you might want to consider a small cheapo one.