One of the thorniest problems you will ever have to deal with as a sound engineer is nothing to do with sound. It is also a subject that I hate to deal with and yet is one of the most important in our careers - wages.
Most sound engineers are self-employed and negotiating wages is part and parcel of our working life. It is also one of the many useful subjects they don't teach you at school. It is however something that obsesses the business community and the phrase "you get what you negotiate" is very true.
I think most of the wage conversations I have ever had in this business have started the same way... "How much do you charge?". Now, this is not the 'we are employing you, just let us know what you want and we'll send a cheque' question. No, this is the 'try not to go too high or you won't get the job, but don't go too low that you don't make any money' question.
There are many techniques to deal with this and they all require a certain amount of nerve. I tend to use the 'well I normally charge this amount.....' pause '... but for you I could do it for..... approach'. This shows you are willing to negotiate but they have an idea of what you are looking for. The one certainty is that if they agree straight away you could have got more! I do however always put in a proviso that if the band take off and the gigs get bigger I will be renegotiating.
I had one manager who wanted to pay me less on club shows and a bit more on big festivals. However what he actually wanted to do was pay me less than I needed the majority of the time and then a reasonable wage on a few occasions. When I suggested that I was very confident in the bands ability and was willing to make a commitment to them by accepting a percentage of the fee, he seemed less keen...
Once you have decided on a wage, get it in an email and also any facts about expenses and the like, and make it very clear what they are getting and what you expect in return. It is a negotiation and you have to fight for everything. If you forget to ask for something don't expect it to be volunteered! So get it in writing but also accept that you have made a deal and moaning afterwards is not on. If you don't set out with clear agreements it usually comes back to bite you.
Remember there is always someone who will do it cheaper than you, but if they ask you, they must want you, so don't sell yourself too cheap! Good luck!