Well if you have children, they are always going to have party's!
Investing a Bubble machine or two.Works on batteries, or maybe electric.
I bought one, and they are Amazing!! you just have to fill up the bubble machine.
You can if you sew...using a sewing machine....make your own 'Banter' strings, that have the triangle...do it in nice colourful material scraps.
Balloons are cheap, use plenty of them and get a balloon pump....Look on Google too, there are plenty of ideas there, to suit your budget.