Side hustles and cash neutral are popular phrases now, I don't remember them being used when I was bringing up my family but maybe they were. I certainly did both things even though I didn't call them that.
I have had a sewing machine for many years and I made a lot of my children's clothes. I used to buy clothes from jumble sales and use the fabric to make clothes. Voluminous polycotton nightdresses could provide a few summer dresses. Men's red shirts can be cut down to smaller ones and even to pyjamas.
Whilst helping at the local playgroup jumble sale I noticed two dresses used for ballroom dancing, one was white, the other lemon. They contained metres and metres of fabric and provided the basis for Christmas presents for my daughters, I made them both a tutu with layers of net and a top layer of bejewelled lycra, I showed them to other playgroup mums and sold every tutu I was able to make from the fabric. I paid 50p for the two dresses and made about 20 tutus, the money I made paid for Christmas that year.
I also made tutus as birthday presents when my daughters were invited to parties, for boys I made superhero capes, I realise this sounds sexist but I was equally happy to make superhero capes for girls though they usually requested a Wonderwoman outfit. I'm sure my kids sometimes got invited to parties because of the capes and tutus.
I earned extra money by doing alterations, sometimes as simple as sewing buttons on.
I tried to choose something every year that could make as gifts and also sell, nappy hangers, lavender bags, crayon rolls and many other items. When eyelash wool was popular a few years ago I knitted scarves and sold them, I paid for Christmas three years running selling them.
Other side hustles included making jams and mincemeat, coconut ice, biscuits amongst other things.
Taking in foreign students, having a lodger, there is a rent a room scheme where you can let out a room for £400 pcm without paying tax, it may be more now. When I worked for a school I had OTT's staying. Overseas trained teachers, some were lovely, some were difficult and then there was Katy, not her real name, her exploits were on previous incarnations of my blog.
I've taken dogs in whilst their owners are on holiday and looked after cats and other pets in their own homes.
I've also done evening and early morning cleaning before and after work and temped during the school holidays. Restaurant work both in the kitchen and front of house.