Total time - 35 minutes
Preparation time - under 10 minutes
Baking time - about 25 minutes
Complexity - easy

Ingredients
4 eggs – one dozen package costs about $2. So, four eggs will cost $0.67
1 cup white sugar – 4lb. package of sugar counts 7.7 cups and cost about $3. The sugar will cost $0.39
1 cup all-purpose flour – 5 lb. bag of flour which includes 9.6 cups cost about $3. The ingredient will cost you $0.31
1 teaspoon baking powder (optional) – less than one cent
dash of salt

Cream
2 tablespoons butter – 16 oz.(453g) package of butter contains 4 sticks. Price of the ingredient is about $4. Each stick counts 8 tablespoons. So, if one stick equals to $1 and you need 1/4 or 25% of that, it will cost $0.25
2 tablespoons cream cheese – 8 oz. package includes 16 tablespoons of cream cheese and cost about $2. 1/8 of the package will worth $0.25
2 teaspoons cocoa (optional) – 8 oz. container of cocoa costs about $1.50 and counts 48 teaspoons. It will cost you $0.06
3 tablespoons white sugar – 4lb. package of sugar contains 128 tbsp. and cost about $3. So, sugar will cost $0.07

Cost calculation of sponge cupcakes ingredients

Note that the actual cost of the ingredients may vary depending on where you live, seasons, discounts, or quantity of buying products.

Conclusions
The sponge cupcake recipe is one of the cheapest while still extremely delicious. The out of pocket expenses for dough and cream may cost you as low as $2 or under $0.17 for each muffin. If we compare the cost of our $0.17 homemade sponge cupcake with $0.50 purchased one, we will get $0.33 of saving or about $4 (0.33 x 12), assuming you will make only 12 cupcakes once a week. By multiplying $4 and 50 weeks, it will yield to $200. Of course, depending on size of family, some people might have to bake much more cupcakes.

Cooking directions
1. Accurately and carefully separate egg whites from yolks. It is still ok to have some whites in yolks, but not vice versa. It might be nearly impossible to beat really good the egg whites with sugar, if there will be some yellow spots of yolk in the mixture.
2. Using a mixer, blend all four egg whites for about 1 minute. Then gradually sprinkle on the sugar and beat until stiff peaks are formed. To make the mixing easier, make sure that you are using good and fresh eggs. Quality of eggs play tremendous role in the success of the treat. Leave the last tablespoon of sugar for egg yolks. To know that your egg whites were blended well, they should increase few times in size and be very dense.
3. Beat egg yolks with one tablespoon of sugar for about 2 minutes.
4. Preheat oven to 375 degree Fahrenheit. Place paper liners into a cupcake baking pan or grease and dust it with flour.
5. Quickly combine the egg whites and yolks with flour, mix the mixture well, and fill the pan about ¾ full. The trick is - do everything fast. After that immediately place the cupcakes into the preheated oven.
Note: If your eggs are very well beaten, then you do not need to use baking soda or powder at all. However, when in doubt, then it is better to add something in order to give proper rise to the muffins.
6. Bake 20 – 25 minutes till they become golden brown or until ready.