I would actually caution against buying too much of any one particular item inc formula.
For starters hopefully as you want to you'll be able to bf and even if you can't (which is rare) not all items suit all babies.
I bf to start then milk dried around 10 months in.
It was very expensive trying to find the bottles, trays and formula which best suited dd
The 1st 3 formulas we tried made her instantly vomit, she couldn't manage the silicon teats and we had to find old fashioned rubber ones (much softer and more like a natural nipple) and the long style thin bottles made her very windy.
So get a couple "options" of each thing.
Eg I've heard SMA suits actually quite few babies as it's quite rich. Aptamil suited my dd best.
With the ready made milks now I wonder if that's a slightly cheaper way to test formulas? I know per ml they're expensive but short term might be cheaper than buying a large tin of a formula that turns out no good for your baby - which is what we ended up with! Several large expensive tins of powdered formula that only got used for 1/2 feeds!
A good bottle brush is essential, we had an electric steriliser which worked fine, but I hated doing sodding bottles such a faff!
Wash, rinse and then sterilise and then if you bloody drop something or otherwise cock up gotta start all over again!
I know it's frowned on now but I used to make up a days worth of bottles in one go as found that easier.
As long as you cool the bottles quickly and store in back of a well functioning fridge it's fine.
I wouldn't bother with a bottle warmer they take bloody ages! Far quicker to have a designated jug or similar which you pop bottle into then pour boiled water into so its surrounding the bottle and it quickly reaches a suitable temp if you've a baby who won't countenance cold/room temp milk
If you're out and about a lot insulated bottle carrier also good to have although again with the ready made milk if you can afford to use that instead then you won't need.