Actually, it's more the opposite - if you just want to print a few at a time to send to relatives, it's a lot cheaper to print your own, as the delivery charges dwarf the price of the prints themselves.
Unless you live close to a Walgreens / Walmart / Target. Then you can upload the photos and just pick them up directly from the store when you're ready.
We have one such service here, but they have a per-order charge that's only 50 € cents below their per-postage-order charge. Their pictures aren't that great quality either, unfortunately.