Many time I would buy a shoe and it would need stretching. The easy way is to take it to a shoemaker and he would do it for you. However, this would set you back a few bucks.
I have used 3 ways to stretch that would cost almost nothing
1. Take some newspaper and wet ,making a newspaper pulp .' This reminds me of when I was at school we used to made a models with newspaper pulp.' Stuff the pulp in a plastic bag and push it into your shoe. Leave the in the sun for 2 days and the shoe will be stretched. As the paper dry's the paper will expend and so will your shoes
2. A similar method can be used with water. In this method all you need to do is ,take a plastic bag add some water into it , push the bag into the shoe and freeze the shoe. As the water freezes ,the water will expend so will your shoes.
3. You can use a potato . By pushing it into the shoe. this method will take longer
4. Or simply wear a thick pair of socks and walk around the house. this method is a pit painful .