Have you raised money from your friends for your startup? 
russell: Dont ask for what they cant give.  $1000 is reasonable.  If you ask for large amounts and fail, you could be sued and you will loose because you will have violated securities laws.If I were you, I would draft a short letter stating what you were going to do with the money and state that the venture is highly speculative and likely to fail.  This doesnt protect you but sets the right level of expectations.  I think you need to state what the expected results are.  I suggest a non-recourse personal loan with an understanding that this turns into stock.  I am neither a lawyer nor an accountant.  If you want legal advice see one of them.