Hi Juuule
finance is always a problem with home ed Especially with 4 children, it must be hard. Our local group usually has a policy of charging per family rather than per child, so that larger families are not excluded, maybe you could have a word to see if your local group can do the same. When I have been negotiating to bring a group I always really emphasise the poverty bit, and usually manage to get quite reasonable rates.
The National Trust does education group cards for £17 per year (it might have gone up now) with which 50 people can go into any NT property free if prebooked. Maybe you could talk your local group into joining together to get a card? Or individual families can have them too. There are always free activities like walks, scavenger hunts, visits to local museums and parks etc, if you want those sort of activities, maybe you could arrange them?
We have one day per month with a local nature reserve, which is free of charge, and our group has also been successful with getting funding for over 13 year olds, so they have had some courses arranged for them - my dd will be old enough next year, so looking forward to that
If there is something the kids specifically want to do, that you can't afford, how about them raising the money themselves in some way? My dd has had toy sales on the pavement in front of our house before now when she has needed cash for something special, or she has made lavender bags to sell, or we have done a car boot sale with her etc, etc.