No, you did not read wrong, I did not add an extra 3 onto the price. $338.00 for a pair of jeans purchased for $4.00 at the Salvation Army.
Vintage Levis Big E Jeans were manufactured prior to 1971 and are highly collectible even in bad condition. If you have not figured it out by now the easiest way to identify a pair is to look on the red tab on the back pocket of a pair of Levis. If the E is capitalized on the red tag, chances are you hit the jackpot as long as they are not fake. Run a search for Levis Big E in the reviews and guides section of eBay to learn more about these jeans.
Before you check every pair of Levis at your thrift store (there will be many) you might want to ask around if you know someone age 60 or older to see if they still have any vintage clothing they held on to.