I'd love to read your advice.
Here in Australia our summer is coming up, though right now my spring weather is still cold.
I decided last year to try a new approach with my summer casual shopping, which typically I have bought very cheaply (ie $25 dresses, $10 tops). This summer I want to go higher quality and put more thought into it.

I have about $230 that I can spend, and think that could get me 3-4 items. One will have to be a new "high summer dress" as I keep ruining my old ones (my high summer capsule doubles as lounge and casual clothes, and thus seems to get more stains).

For the rest, I should buy at least one "bottom" which is my least liked category. I'd like to try a skirt but have had very bad luck with them.

What I'd love to hear is
What were your best / most worn items in the summer casual category?

If you had only 3 items to update this area of your wardrobe, what would you suggest?

I should point out, to inform your suggestions, that it gets very hot in summer in Australia. There are many days over 100, some over 110 and quite a lot in the 90s. I don't expect to wear jeans for many months, and even denim clams are often too hot.