Just wanted to say, 'what skybie said'
With DD1 I bought a whole range of different bottles 'just in case', didn't use any of them until she was 8 months old. With DD2, didn't even bother buying any bottles in advance until I weaned her, at 10 months of age.
There are sooooo many different bottles and teats on the market, a bit like dummies really. And you won't know which one bub will take. You might try 12 different bottles until you find the right one.