RE: trying but where 2 start??
you'll definitely need more than 1kg :) if you can't afford much equipment to start with perhaps you could do lots of body weight exercises - squats, push ups, dips, chins - to build a strength base. and buy equipment gradually when you can afford it? you could make your son part of your fitness lifestyle - you could do chins when you take him to the park, go rollerblading, bike riding or swimming together etc. he'll probably end up loving you even more for it :) good luck!