Here's a way to stretch those tight shoes of yours and you don't even have to spend money and you don't even have to wear them around the house for hours.
Fill the plastic bags with water. The amount would depend on whether you are stretching just a portion of the shoes or the entire shoe. As the picture shows, I'm only stretching the top/toe area of the dress shoes, so I only filled the bags 1/4 with water. If you are stretching the entire shoe, you need more water. Just add more/less water until you have what you need to fill the portion being stretched.
Step2
Close the bags and insert them into your shoes, making sure to fill them out completely. It would be kind of like molding your shoes with the water bags from the inside.
Step3
Put them in your freezer or outside if it's cold enough to freeze the water. We all know that water expands as it freezes, so while the water is expanding, it is also stretching your shoes out.
Step4
Once the water bags are frozen or on the next day, take the shoes out and let them thaw for a while, 45-60 minutes. This will make it easier to take the frozen bags out and to prevent damage to your shoes.
Step5
After the bags are out and once the shoes are room temperature, try them for fit. Of course, you could try them right away if you don't mind cold shoes. If they are not as loose as you want them, keep repeating the process until your feet are happy.
Tips & Warnings
Do not pull the frozen bags out the shoes before thawing them. This could damage your shoes.
Only you know your shoes best. If the material is not made for cold weather, then don't use this process.