Once...

Once upon a time, there was an eight-year old boy named Radhwan. Radhwan was a spendthrift boy. He loved buying a lot of candies and toys more than he needed. One day, he wanted to buy a nice gift for his friend because his friend Ahmad got a full mark in math. However, Radhwan did not have enough money in his money box that his parents gave him in order to make him learn how to save his money. So, it was difficult for him to ask his parents for money to buy a gift for his friend because he did not listen to his parents' advice. Therefore, he was thinking a lot how to find money. He finally decided to borrow some money from his friends, but his friends did not have enough money. Radhwan regretted spending a lot of his money on toys and candies. So, he sadly went to his parents and apologized to them for not listening to their advice. At the end, Radhwan learned a lesson that he should not buy a lot of silly things that he can live without.

Are there any grammatical mistakes?