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

Recently updated user guides:

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 12 Oct 2017: IOTA snapshot is typically the culprit when you check your IOTA wallet and find zero balance. Here's what they are for and how to get rid of that zero balance glitch.
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 16 Oct 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.