Kaysibabes: three avenues to follow
look to see where you can cut costs – examine everything you spend and think can I do it cheaper, do I need to spend this.
look to see where you can gain money – are there benefits your mum could apply for (in uk go to citizens advice to check) are their relatives who could help
look to see where you could earn money – baby sitting, dog walking,, watering , mowing, painting, tidying , washing, sweeping, cleaning windows, weeding, baking biscuits, cakes, selling things on ebay
You could try setting up an eBay account and maybe selling anything worth something online? There are a lot of 'how to make good money on eBay' guides all over the place, so perhaps have a read of some of them too.
It's nice you want to help out your mum. Good on you.
You're too young to be able to make much money. You'll be more helpful if you help your mother around the house. Do the laundry. Do the dishes. Clean the bathroom.
Be Robin Hood.
Ask your neighbors if you can run errands for them.