Who doesn't like flowers!
This idea won't even require any special arrangements for the children, but is still a fun and bonding activity for when the budget is tight and the children are still small.
Put a flower arrangement together!
You can usually find the materials fairly inexpensively at a dollar store. A vase, some arrangement foam, some inexpensive flowers, and maybe some ribbon.
You could also grow the flowers in 5 gallon buckets or in your yard. There also may be a member of your ward with a rose garden who may be willing to donate some.
It's kind of like putting a puzzle together, but do it together. Make it as simple, or elaborate as you wish. Make three of them. Take your creation to a neighbor, someone who's ill, a random stranger at the hospital, your home or visiting teaching families, your mum-in-law.
While you're arranging, ask each other this question "Do you feel I give you enough affection in physical touch? What kind of touch do you wish I gave you more of?:"
Here's an arrangement idea from YouTube: