Do you live in the USA? Reason I'm asking is because larger Goodwill Stores have a most excellent "Active Wear" section and I've found some incredible clothing there for almost nothing.
The last time I walked in summer, I had both hot and chilly days. I think if you plan on layering clothes, you'd be smart.
My packing list always includes two zip-off pants (or hiking skirts), two short-sleeved shirts, 1 long-sleeve shirt, 1 fleece, 1 windbreakers, 2 underwear, 2 bras and a rain poncho. I take 2 pair of wool socks, 2 liners, and a pair of flip-flops or other extremely lightweight footwear for evenings. I add in some lightweight capeline or silk or smartwool longjohns for those chilly wet days. You pretty much wear one outfit a couple of days, then wear the other while you wash and dry one.