You can re-key a lock like a pro and at a fraction of the cost. Re-keying kits are available for most lock brands, but they're not interchangeable. You have to buy a kit for each brand of lock used in your home. (If you're lucky, they'll all be the same brand!) They're available in home centers and hardware stores and through online suppliers.
Each kit will rekey six locks, but you can order extra pins if you need to do more. The kit will work on entrance and deadbolt locks, and it comes with two keys and all the tools you'll need, except a screwdriver. But keep your current keys—you'll need them to remove the cylinder.