Putting together hiking clothes for less $ is pretty easy, in my experience. Use 200 wt fleece for insulation--a little bulky and heavy compared to down, but easy to find in thrift stores and discount places. I like 1/4 zip pullovers for less weight than full zip, but still ventilation options. Always been warm enough with this (plus LS shirt and shell, if needed) for PNW through fall.
Sierra Trading Post (online) always has deals on synth and merino baselayer pieces. I like to have longjohn bottoms and a LS top, with SS top for hiking in if the weather is warmer. I switched to merino over the past couple years, which is more expensive than synth but worth it. With coupons and closeouts, I've never paid more than $35 for a piece. Synth works well too, weighs about the same or bit less, and is cheaper and longer-wearing. It does stink after a couple days tho', and eventually the stink seems permanent.
I *do* splash out for nice merino socks. I'll pay $15-20 for Bridgedale, Darn Tough or maybe Smartwool. But I wear these every day, not just for hiking, and can get years (literally) of regular wear out of a pair. STP usually has cosmetic 2nds of major brands for good price. Other people here hike in cheap, thin dress socks from Walmart.
Lot of folks use cheap running shorts--easy to find at thrift shops. Basically, anything non-cotton and light will work--same for long pants. I have a pair of convertible pants from White Sierra, a brand that is fairly inexpensive, not too heavy, and has a few more backpacking-type features than clothes not designed for hiking.
For raingear, I've had decent luck with Red Ledge brand (Thunderlight models) for the same reason--inexpensive, not too heavy, decent features (eg, pitzips). My old Thunderlight WPB jacket in medium weighed ~11.5 oz. I paid about $60, and it lasted several years, including regular use as a shell for downhill skiing, layered over fleece. I've never tried DriDucks, but that's an inexpensive, highly breathable option that gets frequent mention here.
Steep and Cheap online often has good deals. And of course, Gear Swap here on the BPL forums.