There are plenty of free or almost free activities to do with young children. But even most of the less cheap ones are cheaper than childcare!
If you make most of the cooking/food prep a family activity, and get the children involved in a fifteen minute session of housework every day, that might help. Well, not necessarily for the first couple of weeks, but after that!
The cooking will take longer, but my 14 month and 3 year old children can do some basic tasks that keep them happy while I cook, like stirring something, or transferring peelings into the compost container.
For housework, my 14m loves loading washing into the machine and I then use the time to hang up wet washing or food dry laundry. My 3y can wipe counters with a damp cloth or use a dustpan and brush. Their help is minimal, sure, but it trains them and entertains them.
Some of our favourite regular days out include local picnics (even in the rain) with scrambling over logs or paddling in streams (free if we walk a mile or two) and going to the beach in all weathers (50 minute drive is the only expense).
Mine are really energetic, especially my eldest, but lots of running around outside and plenty of training them in good habits are starting to pay dividends, and I'd be sad to miss out on spending time with them.