Hello
I've gone through a gruelling 2 months of chats, interviews and interrogation and was finally offered a wonderful new job yesterday with a fantastic company!
Trouble is, they have only offered me a salary £1k more than my current salary. Although I ready for a change, and have many many reasons for looking for another job apart from money, I'm a bit miffed.
I work in a consultancy field, which means your skills/expertise basically go to the highest bidder. At my current job I know I'm very underpaid, as know what my colleagues charge rates are to clients. Mine is circa 25-40% lower than most.
I'm wondering whether my age has anything to do with it. After my first 'chat' (before first interview) I was emailed to confirm my DOB. I politely requested why (as it is illegal to be ageist when offering jobs) and they replied with 'so we can benchmark you amongst your peers'. I think that really they thought 'ok, so she's 25 going on 26, which equates to X salary band' - they shouldn't be allowed to do this, particularly as my current employer frequently tells me I'm miles ahead of my age bracket in terms of intelligence, skill set and value to the client.
There are other benefits to the new job, which dont have an immediate monetary value; i.e. get 1 day off every fortnight if work 8hrs a day instead of 7.5hrs, slightly closer to home (cutting commute from 1.5hr each way to 1hr each way), better clients to work for, and more stability (current employer not winning much new work).
So I'm going to try to respond to the job offer with a counter offer of a suggested salary. I'm a bit nervous about this, and wondered what you would say if you were in this position?
I.e. do I say 'thanks for your offer, but the numbers aren't really working for me, I was thinking more along the lines of X+8k' - purely as a starting point for negotiation (although if I get it I'd be laughing!)
My previous boss told me openly that I massively undersold myself in my interview for my current job so it's expected in my industry to negotiate on salary. But I'm not quite sure how to go about it!
Any help/pointers gratefully received 
(I should point out I'm 100% aware I'm in a very fortunate position to a) have a job and b) have a job offer with a small salary rise, but in my industry my time literally = money for my employer, so it's important to get the base salary right so I'm not taken for a ride and also so I'm earning the right level of income for the company. Also this job move is part of my masterplan before TTC - aim is to get as good a salary as possible to allow me to put aside cash for the next 2 years and also mean maternity leave it as comfortable as I can make it)