I built PartSavr after getting quoted $580 for an alternator at the dealer. The same part was $171 online — but comparing 6 sites manually took forever. PartSavr does it in 30 seconds. Enter your make, year, and part. We show live prices from RockAuto, eBay, Amazon, AutoZone and O'Reilly side by side — cheapest first. No account needed. Completely free. Average user saves $847/year vs dealer prices.