Hi Rubineski
I understand exactly what you mean -- three children and various permutations of part-time and full-time work later, I now do freelance consultancy, mainly from home, during the hours my older two are at school.
It can be fantastic -- I can't think of any other work arrangement that would give me time during the day to play with my baby and allow me to be there to pick the children up from school, have their friends to tea, go to their class assemblies etc.
BUT the downside is that there is no external discipline and no separation between home-work and work-work -- when you take a break to make a cup of coffee, the washing machine will be ready for unloading. Conversely, just when the baby falls asleep and you need a break, the phone will ring, and so forth.
I get round this because I have very specialised skills in the field of legal consultancy, and there is very much more demand than supply for the kind of work I do. This means that I can put off answering phone messages in the knowledge that my clients will wait if it takes me a couple of days to get back to them. Also I don't have to spend time selling myself, as my phone will keep ringing anyway, and my (few) colleagues are more than happy to pass work on to me any time I need it.
In a competitive field like writing, I imagine you would have to be very much more disciplined than I am, and to have very clearly delineated boundaries between work time and home time. It might be an idea to find a good accountant and a financial adviser and talk through the implications with them. In particular you'd want to calculate how much money you would need to be turning over for the whole thing to work at all.
With regard to costs, in someways you can save money compared with having a proper job (fewer formal clothes, dry-cleaning, travel, sandwiches) but there are extra costs (heating and lighting the house for example, and all the kinds of insurance that employed people get from work) which are worth considering when you do your sums.
But overall, yes, if you can make it work, then absolutely it's worth it. I did have cold feet when I handed in my notice (after all, it's like saying, 'Please stop paying £xx into my bank account on the 20th of each month' ) but I've never looked back.
hth