I recently received a written offer for a developer job with a company that I would love to work for, but I feel like I got low-balled with the proposed salary. (Without going into hard numbers, I'll just say that I earned more doing public school clerical work.) I did some trial work with them at a rate that would have come out to about double what the proposed salary is; it's a full-time position and I knew not to count on that exact number after benefits and such, but I thought it would be in the same ballpark and not a different zip code. I'm not the most experienced developer, but I've been doing full-time work for almost a year now and we discussed my current salary at the interview. (It's just over $10k more than what they proposed.)
I would really like to accept the job, but I can't afford the pay cut that comes with it. My question is: How can I go about negotiating a salary for a written job offer? In the past, I've had 'interviews' to go over the job offer and have been able to discuss the compensation before receiving the 'official' offer, but I've never just straight-up received a letter to accept or not. Is this a take it or leave it situation? What's the best way to state that I can't accept the specifics of the offer without necessarily rejecting the job entirely?