Be Honest;
Tell them what you told us, then inform them that you are willing to take the position with a 3 month salary review.
One job I took $2000/month to start and turned it into $8000 in 3 months. It was a Branch Managers position with a multi-branch, multi-million dollar development company and I desperately wanted the experience before I became their competition
; I got the job because I was willing to take it at 'cost' and prove my worth. The owners couldn't believe it.
I had another position that I took at $0/month for six months!!! The following year I earned over $16,000/month and following that it went to $35,000/month. That's right a MONTH! (I could see the huge benefit of profits and just wanted in the door)
I'm a firm believer in getting the door of opportunity open..... then get in there and show everyone how to make some money! Put up or shut up as they say.
Not sure this will help you out, but my two cents?