What Just Bill said.
I hiked for years without poles. They are nice to have but if I had a choice between hiking an extra 100 miles or having trekking poles, the trekking poles are out. (That is, unless I need them for my tent. But again, on a budget, I'm using a tarp, not a tent.) Prior injuries may change this calculus.
Boot/shoes: Buy cheap trail runners, running shoes, or sandals on sale.
Fleece. Cheap and effective for the weight. I just picked up a fleece for $9.99 at L.L. Bean's end-of-season clearance. Thrift stores are good sources too. They can be bulkier than other options so like always, purchase the pack last.