The last time you could buy worms for a ''few pence '' was possibly in the 50's ... or after the war.
The last time I bought worms ( in the UK) they were £28.50 a kilo.
If you seriously think you can start composting with a few worms forget it.
Make them a house, there is loads of info online regarding building them a home.
Research .. breeding worms .. before you think of composting with worms.
This is the only way you will create enough worms to start with if funds are low.
If you try composting with a few worms, you will just end up with a smelly mess as you will end up overfeeding them.