2，Mum or dad, of course, provide a regular supply of pocket-money, but uncles and aunts are always a source of extra income.

provide a regular supply of …定期地提供……

provide sth. for provide sb. with sth. 为某人提供某物品

e.g. The villagers provided a regular supply of food for the soldiers.

=The villagers provided the soldiers with a regular supply of food.

零用钱的几种表达法：extra income, small gifts of money, pocket money

作者在文中三处用了不同的零用钱表达法，为的是让读者抓住主题，TIP:写作时避免使用同样的词。