Here's the tips I tell "New" collector's.
1. Start with what you like, If you love NES and you grew up playing it or for some reason it is what you want to play and you insist on playing the original then start looking for the games you want to play. Look for lots to start out. Lets say you find someone who has a SNES with 20 games for $100 on craigslist or Facebook and they are all decent games like, Super Mario World, Zelda, Mario Kart, Donkey Kong Country etc, well these 4 games with the system alone can go for over $100.
2. Always go out and hunt, buying on Ebay is only if you want a game right now. (even then look for "make an offer" and get it cheaper) But part of the fun in collecting is the hunt. Start hitting Thrift stores and garage sales see what you can find. Part of the fun is spending a day hunting for deals and you never know what you'll bring home. Also as your collection grows be on the look out for lots at garage sales. You might find a NES with 20 games for $30 at a sale, keep what you need then sell/trade the rest to not only get your money back but have credit to buy games from a used game store or paypal money and now a game that cost $100 will cost maybe $20. I traded 2 copies of Earthbound I found at a garage sale which I paid $8 for the pair for a $300 Turbografx game once. A few months ago I traded a stack of common (but popular) SNES/NES games for $350 credit and got several rare games added to my collection.
3. Hunt the local used game stores, pawn shops and flea markets. Now these usually don't have the best of deals but be smart. Keep your phone on you and when you see classic games and there's something you want, look it up and see what the game usually sells for. If its priced over, pass or try and talk to the seller about a better deal. If its same or just a tad under then always ask seller about a better price, worst case you get a no and you pass. Never be afraid of walking away. If its a way under. (at least 25% or more cheaper) then its a safe buy.
4. KNOW YOUR LIMITS! I can't stress this enough. Ether due to funds or size, If you can only afford to go game hunting once a month with $20 in your pocket then Just look for games under that price and once its gone your done. Also stick to what your limits are. I don't collect PC/MAC games, they don't interest me. I also don't collect Pinball machines due to space, price and upkeep. I also only buy arcades if they mean something to me or just to damn cheap. (even then I have passed) If you start with the mind set, you only collect Nintendo games? then stick to that. Don't bother looking at Sega games, if you set limits then you can't spend as much money.
5. Enjoy the hobby, if you're only doing this because you look at them as an "investment" go find a better hobby.
You gotta have love for the games, the art, the history and enjoyment when you go hunting and find some games for bargain prices. Part of the fun is finding deals. I respect a collector who hunts for deals in the wild over someone who just hits "buy it now" on a bunch of games on Ebay. When I started people thought I was stupid buying old video games, I didn't care. I enjoyed it.
Half of the time I'm in shock when I find out a game I had for years goes up in value. I keep track of games I'm missing more then I ever do ones I already own. But 90% of games (especially new ones) don't hold their value at all. This is why I hunt clearance bins and see new games for $5-$10 a piece and think okay I'm not out much.
One of the questions I get asked a lot is "How much is your collection worth?" My answer is always the same "I don't know, because that's not why I collect" lol
Another is "What would you do if there was a video game crash and it all plummeted in value?" I always say "awesome, I can finally get many of the games I couldn't afford before." lol
Just don't get into video game collecting because "its a popular thing to do" do it because it means something to you and you enjoy it.
Now most of these are aimed at "Adults", most kids only get into retro collecting because their parent(s) are into it. But if a young 16 year old wanted to know, I'd tell him most of the same I mentioned but also just take what ever money you can afford and go hit some garage sales. Hit any many as you can the more you hit the better your odds. It's pretty much how I got started. I remember taking bags of pennies and coming home with several games.
Of course back then most where only 25 cents a game. lol
