Your dad sounds a bit like mine! Practical (or at least he thinks so!lol) and a little on the cheap side.
Try calling around to the places where you can buy coroplast.... some places will give away good size scraps for free! That's how I got mine... I just taped them together. Or maybe you can find some used peices that people once had for signs, but no longer need.
You could also probably score some free fleece... ask your neighbors or friends if they have any old fleece blankets that they don't use anymore.
Like others have said, they might just be bored. It's easy to make toys for them with things you have around the house. A paper grocery sack is very amusing to them, long soda boxes with the ends cut off make great tunnels, empty TP tubes stuffed with hay are fun too.