Today I had a job interview. I was offered the job. I was told about the payment package. I was initially not satisfied and tried to negotiate for a higher salary during the interview. The boss was reluctant to offer me higher. I agreed with his offer. Now after coming home, I felt the offer was a bit low for me. It is actually less than the market rate for the position.
The company itself is a start-up company, just newly opened. That's what the boss said when he justified his offer. He said after few months they might review (I don't know if he's serious). I will be starting work after 2 days. Since I am not too satisfied with the offer, can I still negotiate before I go to work? I can call him up tomorrow and talk to him about the salary over the phone. I am thinking of saying that the salary is less than the market rate for the position considering my qualification and experiences. What should I do?