On any street corner in a Progressive city that has over 100 Murders a year. If you dare. Otherwise, everyone else's advice on intenet deals.
IF you are looking for 9mm, shopdunns.com has an OK price for blazers 9mm fmj - 1000 rounds for 239.99 delivered, no tax. Basically 12 bucks for 50 rounds.
PMC is perfectly fine ammo.
Georgia Arms offers good plinking ammo at a good price too.
midwayusa.com ...... great selection ...... In 9mm I buy Federal or Finochhi ($12.50 box of fifty) .... always got coupons (google) ....