The song is partially about drugs: straight world=no drugs, real world=drugs. "Go for credit in the straight world / Look a dealer in the eye" Means a person can say apply for a credit card at a bank with confidence, etc. "Go for credit in the real world, won't you try?" Means it is impossible for a drug addict to have the same confidence / attitude when asking a dope dealer for drugs on credit. Can't be done.
The song is partially about drugs: straight world=no drugs, real world=drugs. "Go for credit in the straight world / Look a dealer in the eye" Means a person can say apply for a credit card at a bank with confidence, etc. "Go for credit in the real world, won't you try?" Means it is impossible for a drug addict to have the same confidence / attitude when asking a dope dealer for drugs on credit. Can't be done.