I generally go to a locksmith for that kind of thing. Locksmiths come in 3 flavors.
- Scammers and lead-generators
- Outbound locksmiths who want to drive their truck to your location, and charge you a king's ransom for the privilege
- local community locksmiths with a retail shop who are happy to let you bring your lock-sets into their shop and charge you a sensible price (for a locksmith)
Use the third kind. They're the hardest to find, natch.
That said, the big-box stores do have a possible option for you. One lock manufacturer (don't recall, except they actually do have a reasonably well-reputed history in the lock business) has a mid-consumer-tier product where you can re-key the tumbler yourself. It's pretty slick.
You stick the old key in. You stick a special slotted tool in a tiny slot. This allows you to turn the old key in a weird, awkward, backward way. You pull that key out, put in your new key, and then do some other twist with it. Voilà - your lock is now keyed to the new key.
We're not a shopping site so it isn't really for me to say the brand, but you shouldn't have any trouble finding it.
One more thing about buying consumer tier locks at the big-box store. Look at the package. That package came in a cardboard box which holds 4-12 packages. Flip the package over. You'll see there's a "Key Code" displayed somewhere on the package. Every package in that box has the same Key Code - go look! That's handy if you want more than one package's worth of locks keyed alike - in fact, that's why they do it.
However, it also means anyone else who buys that lock, that store, that time, has a key to your house. Ewww. For this reason, when I buy locksets, I buy them at a store far, far away from my usual paths.