How to back out of a sketchy job interview?

i have dealt with Vector Marketing in the past. They lied about things and they wanted me to pay money up-front. They hid what they were doing. They didn't tell me that they sold expensive custom knives. In my opinion, they are a terrible operation and I would never work for such a company. When I went for the interview, the interviewer gave me bizarre looks. The whole thing was weird and bizarre. It is your choice what to do, but I would suggest telling them -- in a nice way -- that you have changed your mind.