The last set I got from the dealership were $18. The locksmith wanted $45. Keep them lubed with oil or graphite and you'll never need to replace them again.
Btw never use wd40 in locks.... Itll ruin them.
WD40 is a great solvent to clean the locks. Just be sure you let it evaporate before using graphite. In the Southwest I never add oil to any locks. Oil attracts dust which we have plenty. We have fine silt on our dirt roads that will get into everything. Oil and dust mixed will gum up locks.