I am a very big lover of condensed milk, and I'm going to share with you how I make mine at home. Its very easy and gonna save you lots of money.
1 cup of sugar
1 cup of boiling water
4 cups of skimmed milk powder (or less)
Pour butter and sugar in a blender, add the boiling water and blend very well.
Add the skimmed milk powder, 1 cup at a time blending after adding each cup until finished
And thats all it takes, it may look very water but will thicken when it cools down.
Pour into a jar or container with lid and refrigerate.