We have just got a kitten and he is lovely. However, my children are both at school and I work from home so he is really easy to look after. He is really good company and sleeps at my feet while I work and is always with whoever is in the house. If we were out all day I would have got 2 but he loves our company and someone is always around.
I would probably look at it as something to look forward to in the future when you have more money and your kids are older. Kittens do tend to get mauled by younger kids unless you are constantly watching! Plus keeping them indoors at first is hard especially when it is hot and you want to open back door!
Costs so far for the kitten are:
£200 for kitten
£30 for first injections
£20 for 4 months worth of flea/worm treatment from vet
£30 for neutering (not yet done or paid but will come up soon)
£8 for microchip
Equipment including bed, litter tray, bowls, scratch pole, carrier, toys etc came in at around £100.
Kitten food + biscuits is relatively cheap at the moment but will increase as he gets older and eats more. Tesco kitten pouches are only £2 for 12 (he has 2 a day now) and Purina cat biscuits are £6 for 2 big packs.
Litter packs are £2 a go and last 5 days I find. Also you need to scoop the poo each time otherwise your house will pong. I wouldn't want that on top of baby nappies!
Insurance is around £8.50 a month lifetime and covers up to £2000 per condition per year but would still cost £99 upfront per condition.
I will have to have a cat flap installed soon which may cost a bit but am not sure! Also if you go away you need someone to look after them or a cattery costs about £10 a day per cat.