You don't need much to get started. Plus now that my wife has a plentiful supply of gifts for people she goes out of her way to make sure I can soap!
Plastics with 5 is fine for mixing lye. A lot of plastic pots that food comes in is fine and I often use an old margarine tub for measuring my lye in to and then the water is in an old stock powder pot and I pour the lye in to the water in that. To test if plastics will stand up to then heat, pour boiling water in to them (in the sink!) and see what happens. Even then, I can use old cream pots once if I have them in cold water when I pour the lye in.
For moulds, you can use silicone baking forms which are not expensive. safety goggles and gloves aren't overly costly - in all, to get going to see how you get on doesn't have to cost a lot of money at all. Stick to supermarket oils (you don't actually need butters and so on) - they are more expensive in the long run, but again you don't need to order 20kgs of coconut oil, you only need enough for a few basic batches.
Then a stick blender and a good scale most people have at home anyway, so to get going you'll need less than the cost of a meal out for you both.
Once you know that you actually enjoy making soap, you can look at getting better moulds, buying bulk oils and so on, but no need to go crazy spending from the start if it is a hindrance
