It's a tricky decision and I think you're right to consider it, though also try not to panic and don't get caught up worrying by those stupid articles claiming it costs £50k a year to raise a child and that sort of nonsense!!
Personally, I have no fertility issues and I chose to do home insemination with a sperm donor from Pride Angel, so getting pregnant cost nothing (well it cost about £200 in ovulation testing kits, pregnancy tests, little plastic cups & syringes, train fares & hotel room lol).
I've also chosen to move into a large shared house with two friends - one is a very close friend who will be helping out a lot with the baby, the other is also a good friend but will stay in more of a housemate/occasional babysitter role. So my housing costs now are about 60% of what they were when I was renting a flat by myself, and I'll have live-in support and other adults to talk to. We picked a house on the side of London that's closer to my family (most of them are about 1 hour away).
House sharing is really hard work but when it works out, you get so much more support & space. Do you know any other single parents, or close friends who would be happy to share a home with a mum & baby? Several of the late 20s-early 30s parents I know in London live with housemates/lodgers or paired up with other parents to live communally.
I know that not everyone can or would want to make those choices about conception or housing, but that's how I'm going to make it work and I'm happy with the situation.