There were piles of free stuff at Internapalooza, the annual gathering of some 3,000 tech industry summer interns. In the club level at the San Francisco Giants’ stadium on Monday evening, name-tag-sporting millennials travelled in packs of three and four as they scooped up branded T-shirts, tote bags, water bottles, Moleskin notebooks, sunglasses, argyle socks from Zillow, mobile device charge pads from eBay, winter caps from Google, flip flops from Andreessen Horowitz, and – the overall favorite – selfie sticks and throw pillows from YouTube.

Almost everything was free. Everything except the popcorn.

“They’re taking things that don’t belong to them,” said Billie Feliciano, 68, who has worked concessions at Giants baseball games since 1976 and was manning the Doggie Diner, where a hotdog could be obtained with a voucher but a bag of popcorn would set you back a few bucks, if you were not one of the lucky first through the door. (Organizers paid in advance for 500 bags of popcorn; after that the snacks were for sale.)

“They don’t even ask,” she added.

Internapalooza, which is touted by its organizers as “the largest gathering of interns in the world”, provides an inside look at the peculiar cultural initiation to the tech industry that thousands of computer science college students receive each year: an education in coding, entrepreneurship, and – unlike the grunt work and drudgery of other industries’ internships – a certain amount of privilege.

Summer interns at major tech companies make astonishingly high salaries. According to an anonymous survey by a former University of California Berkeley student, Snapchat interns earn $9,000 a month, plus a $1,500 housing stipend. Monthly salaries at Pinterest ($9,000), Twitter ($8,400), Facebook ($8,000), Slack ($7,700), Uber ($7,300), Apple ($6,700) and Google ($6,600) are not far behind, and many companies offer generous housing, relocation and benefit payments.

Interns at Internapalooza. Photograph: Courtesy of Internapalooza

“Most people in tech internships are more talented than the employees at their companies,” speaker Keith Rabois told the crowd. (A member of the PayPal mafia and successful tech investor, Rabois recounted his unusual path to tech via Stanford law school, but omitted the incident in 1992 when he shouted “Faggot! Faggot! Hope you die of Aids!” outside the home of one his instructors, which he later said was intended to provoke discussion about free speech.)

“A lot of interns here don’t just fetch coffee,” said Terry, an intern from Canada who was interested in getting a job after school at Palantir. “We actually do the same work as software engineers but get paid less than them.”

“There’s a lot of inequality, but a lot of opportunity,” said one Google intern, a rising senior at Harvard. “I was in an Uber the other day, and my driver was thrilled to be in Silicon Valley. It’s like the American dream. Anyone can teach themselves to code and make an app.”

Swetha Revanur, an intern at HP who will start at Stanford as a freshman this fall, worried that she might face ageism.

“They tend to look for upperclassmen, and I’m trying to push those boundaries,” the 18-year-old said.

(Revanur’s fears are likely unfounded. Rabois warned attendees that, like elite athletes, they were already close to the “prime of [their] careers”.)

Took 3 hours to get into #Internapalooza and missed majority of the free stuff but still had fun ‼️💃🏽 pic.twitter.com/GaD0LYuOk7 — Jade (@Jaderss123) July 12, 2016

Despite the promise from a Microsoft recruiter of an “exclusive afterparty” with “hella noms, lots of dranks, the best beats” and “Yammer beer pong tables”, the event itself was largely business. A special table set up for Pokemon Go players stood empty while attendees lined up at company tables for brief conversations with recruiters.

Dropbox was favorably positioned by ping pong and foosball tables. Palantir was, appropriately enough, tucked away in a dark corner.

“We’re the guys who you passed on the way to Snapchat,” joked Mark Davis, a senior director of software engineering at GE Digital. “We’re also the guys who could buy Snapchat and not even notice it on the P&L [profit and loss sheet].”

Google – generally considered one of the most elite internships and employers – had more real estate than anyone.

“The only thing I can say is they do have the outside patio with the free churros,” said one Google intern about the pecking order.

Testing out VR headsets at Internapalooza. Photograph: Courtesy Internapalooza

Attendees were provided with a special talk on “shit no one tells you” from Michael Callahan, the 32-year-old CEO of AfterSchool, a social network for teens.

After explaining that college would not prepare students for tech jobs due to “old teachers”, Callahan asked how many of the attendees spent their Friday nights like he did, working in the library.

“This is weird, and I hope this doesn’t sound racist, but it was me and the Asians,” he said, to no laughter. “Me and the Asians cranking it out on Friday nights.”

One intern braved a question: “At which point do you think it’s the right moment to start focusing on other things in life so when you’re 80 you don’t feel like you missed out?”

Rabois’s response invoked elite gymnasts who must miss out on school and friends as teens in order to make it to the Olympics.

Such hard work was key to his success, Callahan said, before explaining that success was defined as money, reputation and happiness. Happiness could be obtained by enjoying your job at a company you like. Reputation was easy if you worked for a company like Google. Money was a bit trickier, though.

Michael Callahan, CEO of AfterSchool, speaks at Internapalooza. Photograph: Courtesy of Internapalooza

“You will never become rich joining a company as employee number 1,702,” he warned.

Callahan ended his talk with a quote from Dr Martin Luther King Jr, which he said he used in his email signature.

Of all the lessons the tech interns were learning in Silicon Valley, one of the most common was an aversion to being quoted talking about their companies in the media. Shortly after granting an on-the-record interview about her internship and background, an Apple intern tracked down this reporter, demanded that the interview be retracted and the reporter’s notes turned over, and called an attorney to discuss her legal rights in the situation.

The quotes in question?

“We’re completely trained in all kinds of secrecy,” the Apple intern said. Asked what the training entailed, she responded: “I can’t discuss that either.”