If you're a college student, Christmas and birthdays are prime opportunities to grab a new piece of audio gear. A really good set of headphones these days will run you at least $300, and let's be honest — if it's your money, those 300 clams could also buy a massive amount of ramen and beer.
I've always been interested in audio equipment, but I've never been able to afford the new, top-of-the-line stuff. And as soon as I started making enough money to possibly afford some of that stuff, a baby burst into my life to claim the extra income. I'll take your pity, but just know she's "OMG I'm dying" level of cute and completely worth it.
So I've always been keen on sourcing good audio gear from the past to get the sound I want now. Interestingly about audio, so much of the technology was perfected so long ago that the "new and latest" may not automatically equal "best you can get." Much of the industry has moved to facilitate convenience and portability rather than to push the boundaries of sound quality, and the pursuit of the former in many cases has led to a degradation of the latter.
That means great sound existed before Bluetooth, and you can find it at a discount. An old 1990s-era receiver at a garage sale for example can be a really perfect piece for your dorm or apartment, if you know what you're looking at. People everywhere are interested in used gear, so typing the brand and model number into the Googles will likely lead to a discussion forum where someone has already asked something like "Pioneer SX-1250 for sale for $50 ... should I take it?" with the usual host of responses following.
This kind of information is speedy to access, but it can also lack context and inhibit understanding. Sometimes you just can't beat a real live person who can answer questions and even offer historical background to make your choices easier.
Boulder's got a couple great sources of curated used audio gear where knowledge is just a question away. Absolute Vinyl at Arapahoe and Connestoga Street (in the strip behind Snarf's and Ozo Coffee) is my usual go-to for vintage and used stereo stuff because they really know their audio history and vintage products, and they have a ton of options.
Another great source for vinyl in Boulder is Bart's Record Shop on Folsom (same parking lot as Village Coffee Shop), and like Absolute, Bart's has more than a few pieces of stereo equipment for sale. If you're lucky, you could put together a complete system, including a vinyl library, in an afternoon without leaving the store.
This list wouldn't be right without old you-know-who. Craigslist is a speedy source for electronics, but you need to have your Ctrl C, Ctrl T and Ctrl V keystrokes ready to do your research. The lineup on Craigslist won't be curated and guaranteed awesome like you find at the record stores, but chances are decent that you'll be able to browse some lower price points and cheaper selections.