I was verbally offered a job and the manager insisted that I start the day after the following day from the interview; so two days after the interview. I left the interview unsure of the offer the manager called me later that day and I agreed to take the position. At this point, I was told that I would get an offer letter the following day and would start the day after that. Later that evening I was asked for a code sample. I have yet to receive the offer letter the business day is about to close.

I've been mostly contracting and usually answer technical questions or show samples at the beginning of the process and find this situation somewhat odd. Is this a common practice? Should I call the manager before business closes?