Personally, I wouldn't buy any. If you need them you can get them then. I had to express in hossy for DS1, but they provided everything I needed anyway and then DH got what I needed for home. I can see that there is some use in having these things in advance, but I also think it a bit like setting yourself up to fail.

What I would do is join the ABA now and attend a bfing class. This is the best preparation you can do for bfing. Then you will be a member, so you can hire a pump if you need one (in the early days if you need one an electric one is going to be really handy). You will also know who to ask for help!

ETA- whoops just saw that you are an ABA member already. Great stuff.