Below, in randomized order, I've listed some of my favorite sites for trading, tracking prices, and getting the latest news. Let me know if I've missed any solid ones!
1. Coinbase (Limited Trading)
By far the easiest way to purchase Bitcoin with USD. Unless you have some cryptocurrency already or you can buy from a friend (I don't recommend that), you'll probably have to start here. Once you have Bitcoin, you can access a lot of other crypto exchanges that will allow you to use your Bitcoin to invest in other coins.
2. Binance (Trading/Exchange)
This is my favorite exchange. By a mile. They constantly add new coins and have tons of volume. They also distribute fork coins - like Bitcoin Diamond, Cash, Gold, etc.
3. CoinMarketCap (Price Tracking)
Complete market-cap rankings for cryptocurrencies, including charts, links to exchanges where coins are available
4. r/CryptoCurrency (News & Rumors)
Reddit is easily one of the best places to get up-to-the-minute news and rumors regarding your favorite cryptocurrencies or the market in general. Use good judgment, don't believe everything you read, and contribute back to the community when you can.
5. CoinDesk
"CoinDesk is the leading digital media, events and information services company for the digital asset and blockchain technology community. Its mandate is to inform, educate and connect the global community as the authoritative daily news provider dedicated to chronicling the space.
Founded in May 2013, CoinDesk reaches over 5 million unique visitors who come back 16 million times a month. Across Twitter, Facebook, and LinkedIn, CoinDesk has over 275,000 followers with nearly 100,000 people subscribed to its Daily and Weekly newsletters. It also has the most widely sourced Bitcoin Price Index, with The Wall Street Journal, Financial Times, and others incorporating the BPI charts into their reporting."
6. Cryptocurrency Calendar (News & Rumors)
Community-sourced updates, news, and rumors regarding cryptocurrencies that might help you make better trading decisions. Be very careful with the information that you read here...but there are certainly opportunities to make profits from learning about announcements before they go mainstream. Anything <75% is something that I would highly doubt.
7. Bittrex (Trading/Exchange)
"Bittrex is a next-generation crypto trading platform built and operated in the United States by crypto enthusiasts with extensive development and security background. We have over 50 combined years in the computer industry at companies like Microsoft, Amazon, Qualys, and Blackberry and have made careers developing secure and scalable software."
8. The Merkle (News)
"Welcome to The Merkle, founded in June 2014 we strive to bring you the latest Crypto, Finance, Infosec, and Tech news. Our goal is to produce interesting and educational content and become a valuable resource to those looking to keep up with these topics.
The Merkle has a dedicated cryptocurrency news section and also includes a variety of educational articles relating to Bitcoin, you can find anything from how to make money with bitcoin to how to create your own cryptocurrency."
9. GDAX (Limited Trading)
Owned by Coinbase, GDAX provides a more sophisticated trading experience for the big 3 (BTC, ETH, & LTC). Limits, margins, and depth charts are available. Reviewing limits can be accomplished by uploading your ID, similar to Coinbase.
10. 4chan/biz (News & Rumors)
This one requires patience, caution, and an accurate BS-meter. However, you can often learn about rumored improvements, announcements, or other crypto-happenings long before any mainstream media/retail investors will.