Most jobs will require some IT skills. Children with a computer at home do have a distinct advantage over those who do not. However, even if you cannot afford to buy one, your child may still be able to use one in the public library, at school during breaks and homework clubs or at Internet cafes. It just isn't quite as convenient or reliable - your child will have to compete with other users. Demand for computers at after school clubs can also be quite high with no guarantee of a place.
New software demands more memory and a higher specification.
For this reason, I would never recommend buying a second hand computer unless you're getting a very good deal on a fairly new one. A computer purchased for your child at the age of 14 would be more useful for school work than one purchased for a child at primary level. A computer by itself is pretty useless - you will also need appropriate software to do the work. Word processing Clear presentation of work. No spelling mistakes because all text can be spell checked.