Hello 5mummy... For me, i got some hand-me-down infant clothes from my sister's boy. Hand-me-downs are really comfy and seasoned so I like them. If you dont't have, can buy some but do note that 1-3mth babies outgrow their clothes VERY FAST so dont't buy too many pieces.
Milk bottles... any brand will do. I got both avent and medela bottles. Have a few sets so you dont't have to keep washing and sterilising once they are used. Best is breastfeed your baby... do direct latching, no bottles needed! Save money and time...
I dont buy sterilisers... i just use the conventional method. Put all the washed parts in a big pot of water and boil for 10mins.
Baby cot/playpen...up to you really. Some pple let their babies sleep on mattresses or co-sleep. I use a baby cot since my boy's first day. Playpen i only bought later when he grew up and needed a 'confined' and safe place to play.
Diapers.... dont buy newborn size. Use all the samples that you get from hospital/gynae/babyshows and from baby gifts. Coz by the time you finish those, they outgrow NB size. Haha... Buy S size better. At most just buy one packet of NB size diapers.
Cloths for cleaning/wiping is a must for me. I bought a stack. Good to use for burping babies after feeding.
Mittens and socks i also use hand-me-downs.
Hope these help! Anyway just some suggestions coz every parent/baby have different preferences.. Good luck with your first born!