Four students at a vocational high school were arrested and charged with printing more than $8,000 worth of bogus $10 and $20 bills and spending them at area businesses.

The Salem County Vocational-Technical School students were arrested Friday and charged with forgery, authorities said Monday.The students printed the fake money in the graphic arts department at the school's Career Center, said Trooper Daniel Cosgrove, a state police spokesman.

The front of the phony $20 bills all were stamped with the same serial number and the reverse side was printed upside down. Some $10 bills did not have serial numbers and were smaller than legal bills.