DDs early years were, on income support I got an under 18s amount, was paying off one of their loans, had child benefit and about £50 a week child tax credits.
Then I did an apprenticeship, worked Saturday nights and had tax credits and child benefit....it was hard, but there were plenty of free playgrounds around, sure start vouchers worth a couple of quid a week. It meant budgeting carefully and sometimes doing without for myself, but she was always OK.
Things have been better in DS life, probably more than you're interested in hearing about
But what I will say, is genuinely if you're thinking about having a baby on not a very high income, look for free groups, there are lots and lots around, you can keep yourself out of the house every day for free if you live in a fairly large town.
NCT nearly new sales can be excellent (hit or miss a few of the ones I've been to) but the good ones are flipping amazing. I spent £80 the first time I went to one, I filled my car up, high chair for the inlaws, a baby walker, loads of toys, loads of clothes- some he's just grown into! Ebay, and marketplace for second hand so you're not wasting money.
Use tesco clubcard for nappies, make use of pampers vouchers... I've recently had some vouchers in some of DS nappies, when I used them with the clubcard price, it took each pa k down to £2...if I find deals I always buy a month or two ahead nappy wise.
Other than that, try to be a size ahead in clothing.
Have a couple of months nursery money saved up if you can before baby arrives.
If you can stretch to it, save for a cleaner to come in for an hour or two each week for the first few months whilst you gain your new routine.
Batch cook before.
It's all stuff that'll save you money long term, or your sanity in navigating the beginning of your child's life.
All the best.