The most frugal way to celebrate Bonfire Night is to stay home and watch everyone else's fireworks out of the window and we have done this when the children were very small. They were allowed to stay up in pyjamas and sit around the fire waiting for the bangs ! They would have been woken up anyway.
Next most frugal thing is to have a party at home with a bonfire and sparklers and put the emphasis on lots of homemade food and fun in the dark. This worked well when the children were primary school age.
Final option is to buy a family ticket to an organised display or arrange one in your backyard with a strict budget limit.
The last few years we have done a home display but Master Shoestring wants bigger explosions this year so we'll be spending the same amount on tickets for an organised display if the weather is good. Otherwise, we will be back to peeking out of the window as we live on top of a hill and get quite a good view of the fireworks in the valley below !