Very, Very Rich, but it will take time and nobody can know that he is from the future
The stuff he brought with him is effectively worthless because there is no way to show somebody in 2000 technology from 16 years in the future whilst hiding the fact that it is from the future. How are you going to explain away the fact that Joe (Random guy) has somehow invented, perfected and created technology that is literally 100x better than anything the biggest, most expensive R&D labs in the world can produce?
So, you cannot sell your future stuff, because as soon as anybody knows (or suspects) that you are from the future, you're going to find yourself hunted by every corporation, billionaire and intelligence agency on the planet.
How much do you think (to take an example) the US govt. would be willing to do to find out the details of every major war and terror attack for the next 2 decades? If you think the US wouldn't torture you to find out, then also consider the Chinese and the Russians.
So, that is rule #1: You absolutely have to keep everything to yourself.
Personally, I recommend Joe destroys and incinerates everything that came back in time with him (possessions, clothes, jewellry).
Update: He is going to have a really hard time starting out
As pointed out by @vsz in the comments, Joe isn't going to have a legal identity when he arrives in 2000 because past-Joe is already using it. This means that Joe is going to be, for all intents and purposes (and in a very real sense) an undocumented illegal immigrant.
He is going to have to find cash for food and shelter, and then find and pay a forger a lot of money to create an identity for him, and *then* he can do all of the below and become obscenely rich.
Assuming he manages to do that at all. He's in the same precarious position that all undocumented illegal immigrants are in: If you get caught even once then it's game over, and earning any cash at all, let alone enough to buy a new identity is going to be really difficult and/or risky.
Possible solution: have future-joe find past-joe and convince him that you're from the future and you should work together on this
This strategy is risky (If past joe reports him to the police: game over) but solves all of future-joe's other problems. You'd find past-joe, show him your amazing futuristic smartphone, tell him the deepest darkest secrets that nobody else could possibly know about the 2 of you, and convince him to work together with you. He can provide cash and a legal identity, you provide knowledge of the future and using the below, you both become obscenely rich.
So, how to make money
The truly valuable thing that Joe has is his knowledge of the future. The most lucrative information would be knowledge of financial markets (market runs, crashes, companies that shot up/down in value). If joe had a job in finance that exposed him to that kind of information on a regular basis, that would work out particularly well for him.
But even if he wasn't particularly interested in financial markets, your average person will remember particularly big events (the dotcom crash, the 2007/08 crash, the irag/afghanistan wars, 9/11). They'll know the names of big companies (Google, Apple, Facebook, Tesla, Netflix, Amazon etc.) and be in a position to "get in early".
- The dotom crash is just getting started when Joe arrives. If he does nothing but keep betting that the stock market will go down for the next year, he wil make an awful lot of money.
- Apple's stock price increased 100x from 2004 to today
- From its' IPO in 2004, google is up over 20x
- Amazon's stock price increased 100x from 2001 to today
- Facebook is up almost 10x just in the last 3 years
- Tesla jumped almost 10x from 2013 to 2014
- Lehman brothers was worth \$50 Billion in 2007, and \$0 18 months later.
- Enron was trading at \$60 Billion when joe arrives, and will be bankrupt within a year
You get the idea. Joe doesn't have to know the exact numbers, he just has to remember that these things are going to happen and act accordingly.
Additionally, your guy could make a lot of money in the betting market (betting on who wins the US presidential elections, who wins major sporting events, etc. etc.)
This won't make him a ton of money *immediately* (unless he has a really good memory for sporting events circa 2000), but the presidential election is coming up in November. The dotcom bubble is about to burst. There's probably some major sporting event he might remember the outcome of.
If I were joe, I'd borrow some money (say, $10,000) and go make some bets on events he remembers that wouldn't attract attention, probably sports and the election (correctly predicting 9/11 would attract a *lot* of attention. So just don't go there.).
It will take a while to get super rich, and a lot of it won't come until later on, when you get closer to recent memory and more events that he remembers the outcome of come close enough to make bets on. Things like, say, Bitcoin (10,000 BTC bought you a pizza in 2009, and $8 Million just four years later.)
But he should get reasonably rich reasonably quick and things will just keep snowballing from there.