Hi.
I think its great that you are thinking about getting a Kitten, but if you were to get the kitten now and then go off travelling for a few months, you are going to miss out on so much fun! The don't stay young forever, so I would urge you to re-think getting the kitten before you go.
Also, its not really all that fair on the kitten to move it from home to home at such a young age, it will bond with you so much better if you are around alot more of the time.

Why not contact your local cats protection and explain your situation, and offer to foster a cat until you go, then find your perfect kitten when you return. That way you get the best of both worlds.

Okay, so as far as costs are concerned, to feed a quality diet, you are looking at about £5 a week per cat if you feed cat food (wet and dry). However, there are alternatives to cat food, such as raw meat diets, this for me works out cheeper than cat food, but you should read up on this if you plan on feeding this way.

Cat food costs are really the least of your worries, in the first year, your cat will need injections, one at about 9 weeks and one at about 12 weeks, at about £50 for the pair. At about 6 months, your cat will need neutering if its a boy (about £45) or Speying if its a girl (about £65). And I advise microchipping, about £25.
Your cat will also need regular flea treatment and worming treatment, I worm my cats every 3 months, costing a couple of quid a time.

Now what if something goes wrong and your cat gets ill, you have a choice. You can either take out an insurance policy, and pay about £5-£10 a month, if you cat gets ill and needs vet treatment, you will prob have to pay the first £100 (excess), but read the small print.
Or if you have enough savings / and or have a large diposable income, then you may decide not to take out the insurance and pay as and when the cat needs treatment, but if this is the case, remember, vet treatment can get very expensive.

On top of that, you will need (want) to supply your cat with toys, beds, food / water dish. Your cat will also need anual boosters at the vets costing about £35 a time.

I'm really not trying to put you off, but its not only money that you need to think about here, but your free time too.

Keep us posted on what you decide.