BASICS - Where to trade altcoins? What are good exchanges for altcoin trading? Who has lowest fees?

Recently updated user guides:

Blog  19 Jan 2018
First ever iOS wallet for Monero
Coinomi integration will be available soon but Cakewallet is already hitting the AppStore.
Blog  18 Jan 2018
First version of Bitcoin Lightning Network is on the mainnet
LN Micro-transaction protocol on the bitcoin blockchain is currently powering the Blockstream e-shop, and is buggy.
Blog  16 Jan 2018
Terms of Service - Comparison of popular crypto exchanges
Kraken, Bitfinex, Bitstamp, Binance and Kucoin compared.
User Guide  03 Jan 2018
Update for 2018: Smaller cryptocurrency exchanges for trading
Last update 15 Jan 2018: Added Kucoin. Find new emerging cryptocurrency exchanges for your altcoin trading in 2018 (and avoid potential drama).
Feature  29 Dec 2017
All new cryptocurrencies that started trading in 2017
Last update 30 Dec 2017: The list is very consistent with the fleeting mentality of the cryptocurrency markets.
Blog  07 Nov 2017
Hardware wallets and Bitcoin SegWit2x Fork: Ledger vs Trezor
Last update 09 Nov 2017: Both of the top hardware wallet companies have published their stances on the upcoming Bitcoin fork and how they will deal with the missing replay protection.
Blog  18 Oct 2017
Crypto cards for non-EU residents
Last update 18 Oct 2017: Are there any though? It's all over for non-EU residents and what's miraculously left gets scam accusations left right and center. Stay with your LBC cash, folks. There's also LocalEthereum now, don't forget that.
User Guide  12 Oct 2017
IOTA Snapshots
Last update 09 Jan 2018: IOTA snapshot is typically the culprit when you check your IOTA wallet and find zero balance. Updated with the info about reused receiving addresses.
Satire  10 Oct 2017
Customer Support Zen
Last update 10 Oct 2017: Poor things, they are so busy.
User Guide  28 Jan 2017
Back to Basics: How to buy altcoins
Last update 21 Dec 2017: They say you need bitcoin to get altcoins but the fiat to alt markets are slowly appearing on previously bitcoin-only exchanges. For the gambling trading you need the liquidity of Alt/BTC pairs though.
Trading Strategy  30 Mar 2016
Value of Altcoins: Money and Tokens
Last update 20 Jul 2016: Altcoin value: Some altcoins are meant for payments and remittance, some altcoins are network tokens.
User Guide  07 Mar 2016
Earning More of a Cryptocurrency: Interests and Lending
Last update 21 Oct 2017: Cryptocurrency lending, margin swaps and lending bots. Is altcoin lending worth it or better to stick with BTC loans?
User Guide  29 Feb 2016
Best Altcoin Exchanges, Tried and True
Last update 18 Oct 2017: Where to trade altcoins? Which exchanges are liquid, which have issues and which look like exit scam? Updated for 2017/2018
User Guide  28 Feb 2016
Best Altcoin Wallets
Last update 17 Oct 2017: Where to store altcoins? See a list of altcoin wallets, from web based wallets to best hardware wallets.
User Guide  27 Jan 2016
Altcoin trading charts
Last update 18 Oct 2017: Where to get the best charts and charting tools for altcoin trading and technical analysis.