By Ellen Chang Several states have seen gasoline prices drop to three bucks or lower as crude oil prices have continued to decline. Gasoline prices continue to fall in a handful of states to $2.99 a gallon, marking the 50th consecutive day of declines and giving consumers a reprieve as high inflation rates have walloped their budgets. Gas stations in Oklahoma and Kansas are selling unleaded gasoline for $2.99 as of Aug. 4, according to Patrick De Haan, head of petroleum analysis at GasBuddy, the Boston provider of retail-fuel-pricing information. The national average is $4.09 a gallon, while 2…