1) It ranges tremendously. 35K-150K wouldn't be unusual for someone in social psych. But really think about what you need for your research and start from there. Make the case for each item, the Deans may or may not have flexibility. It makes a big difference if the program is in social sciences or life sciences… 100K is cheap for life sciences generally, but alot for social sciences, unless you are a brain/health person.
2) One thing I did is ask for the start up funds to be spread across 4 years instead of 2. These funds often have an expiration date, and that is an easy thing for them to agree with because it doesn't cost them anything.
3) Ask for everything you NEED… and then look for solutions if they can't give you everything. So, for example, if you want a paid graduate assistant for a year and they won't give it, ask if they can give you 2 undergrad work study students, which are partially paid for by the government. Be flexible about how they can meet your needs.
4) Generally speaking, at this phase it is you+the dept versus the dean. The department has a vested interest in you getting the best package possible.
5) Ask current junior faculty at that school if they are willing to share their negotiation packages, and get as many examples from friends as you can. There are lots of requests where you are like "oh, wow, I never would have thought of that"