Milk bottles - currently using Nuk. They cost about $15 a bottle. Was using Avent but didn't like it.
Breast pump - Using Medela, which is more expensive than Avent but offers a wider range of pumps. Electric and dual is the way to go for convenience, especially if you are going back to work.
Diapers - currently on Huggies. Used Drypers but it felt like paper. Huggies is softer. During my baby's first month we were using Pampers as hospital provided and hubby just bought back the same brand. But I was using Pampers only at night, but cloth diapers in the day as more cost-efficient. But someone would have to do the washing. For me, I did it myself.
Formula - Using Soy formula Isomil.
If you really want to BF successfully, I will tell you not to buy any FM AT ALL. dont't even put 1 small tin in the house. Just latch on baby frequently and you will DEFINITELY have milk because they dont't drink a lot at one time, and feed frequently. When I first started out I can only pump less than 10ml. But I just continued to BF her anyway without giving her FM. At 6 months, I am still BFing almost exclusively.
My mistake was to have the FM in my house, then got tempted to give baby FM instead of BF (just because I wanted to sleep more). End up my supply suffer.