Hi, I am really interested in how to sell your first rounds... Like I got an offer for my startup from a ex boss he wanted to give me $300k for 30% of the compa

Hi, I am really interested in how to sell your first rounds... Like I got an offer for my startup from a ex boss he wanted to give me $300k for 30% of the company, valuing it in $1.000.000 I don't think this is a good deal 30% seams a lot, but as I don't know a lot about how the other companies are doing I am quite lost. Anybody have some experience to share ? how much did you give from your company for you first investor ?