With my twins I used a baby bath on the bench for a while, but then they went into the little seats things in the bath.

I also had loads of 0000 and 00000 clothes but being twins my two weighed 6lb4 & 6lb8. I guess it depends on how big your baby will be. I think if you have a couple of 0000 that will do and if you have a small baby perhaps your partner or a family member could go to the shops and buy you more if need be.

As the other ladies have said a play gym. At 7 months my twins still use their play gym thing only now they are always on their tummy, so play with the bits attached to the mat. We have got great use out of this.

We also had swings for the twins that we found came in really handy.

And also some wraps. We swaddled our babies until they started to roll and found they slept so much better swaddled.

Hope that helps.