I was visiting Orange County (ugh) then, and just went to some upscale men's clothing shop/boutique. Shirts were about $100-300 each, pants $100-200, shoes another $100. (I had a very friendly expense account at the time.)
This was south California casual, I guess? Shoes that look good sockless (or wear those little liner socks). Button-down shirts that have some simple design. It was nothing really, and I'd have no problem doing outfits that good myself now, after spending perhaps 10-15 hours reading about fashion and trying stuff out. But at the time it was revelatory.
I am certain that many guys in my position would do fine just going any decent-looking clothing store and asking the salesguy to make you look OK. They're good enough to not let you leave looking like a dweeb. Personally I like some of Banana Republic's stuff, as it's higher quality than Target, and still casual (yet the other half of the inventory seems very "douchy").
People are so vulnerable to social manipulation via clothing and all sorts of other means. The stereotypical programmer person looks down on this, perhaps because they're not comfortable, or because it feels "fake". It might be useful to view social as just another system to be hacked. And in the process, one might realise it doesn't have to be fake and can be quite rewarding.
Yes, I know, this reeks of just blindly following trends and conformity. But we don't say that of other hacks. "Loser! You just shoved some escape characters into a querystring and looked for issues. That's so common, you're such a sheep." Yeah, maybe, but the end result is what matters. And feel free to A/B test versus wearing a "I'm too CSSy for this shirt" tee and decide which leads to a more fulfilling experience.
[The irony of me giving out fashion and social advice. Like someone advising you to "buy a computer with Internet; that's my favourite program".]
I agree with your sentiment about wearing nice clothes for the social hack feeling "fake". At some point in school I made a conscious effort to judge people by who they are, rather than by the material things surrounding them. And even though I'm playing the sheeple's game by dressing nice(r), I try to still give everyone the benefit of the doubt and judge them by who they are. It's paid off; I got a (very welcomed) free lesson in Cassandra at a tech meetup because I started a conversation with someone who other people were avoiding because of appearance.
Adding more to civilian's comment: you will find both good and bad advice in that subreddit. I think a decent wardrobe (fitting shirt, fitting pants, leather shoes, belt) can be acquired for within $500 if you hit Macy's or other department stores. Try not to buy super expensive stuff; clothes and shoes are easy to ruin, and my personal rule of thumb is that its better to buy cheap and replace than to buy some insanely expensive shoes and then be distraught when you spill beer over it or something. Another advice: its all about the fit. If you really want to look good, find clothes that fit really well. Don't try to be 'flashy' or different, it will usually backfire.
If you do go there, please take in account that a lot of the advice there is not really what you want unless you want to look to other 20ish year olds going out to bars/clubs. You will get mileage of going to a decent store and tell them you want to look for: going out/work event/golfing/etc. What loks good for trendy 20's in new york will look out of place/weird at a marina or a friend's birthday party. As everything, context matters!
That made me chuckle.
Mind commenting on what kind of clothes they offered and for what sort of price range?