Hello everyone!

I will be starting another semester of college in the fall, and I want to know what items I should get to give me a good, flexible wardrobe for a few months ( 3 to 4) until I will be able to buy some more. I am currently in California.

The items that I have are:
1 pair sand desert boots (Clarks)
1 pair black leather chukka boots (Aston Grey)

1 pair light grey pants (Express)

3 pairs dark jeans (different brands)

1 shirt "celestial blue" (Express)
1 chambray shirt (i.e with breast pockets and sleeve roll tabs) "marine blue" (Express)

for accessories I have:
1 wide dark brown leather belt (Old Navy)
1 Bulova rectangular face with black leather band

So what should I get to have enough outfits for the semester? I want items that are interchangeable/flexible. My budget is less than 500$, so lke 350 - 400$

Any suggestions would be greatly appreciated,