If you instill joy and love into your children, as often as you can, it will hardly matter to them what they have or do not have. I have seen many of the most joyful children in some of the poorest places I've been.
To them, the only thing that matters is the comfort and love you give them. To feel safe and know they are cared for.
So please don't think your children needs more stuff to be happy. In actuality, that is telling them that happiness is something that can be bought... and will make it a tough lesson to learn when they get out into the real world.
Instead, give them something that is free: Your time.
Do things with them that grow the bond you have for one another. Go on experiences. Eat at fun restaurants (and don't bring your phone). Play games with them. Laugh with them. Take long walks. Read books together. Have ridiculously long meals.
For it is such an important thing for a child to learn early where true joy comes from. Because, if they learn it then, they learn also that nothing in this world can take that away from them... For it came from simplicity, and nothing more.