Let's take a look at trading on Coinbase, since they are the largest US exchange for buying and trading with USD. And they offer two platforms with similar names, Coinbase and Coinbase Pro, which can be confusing.
Say I want to buy $500 of BTC right now. The displayed price is $8761.38/BTC. However, I can easily see the price of BTC being quoted outside of Coinbase is roughly $8718. So the price has been marked up by 0.50%.
The default option is to pay with credit card, where you will be charged a "Coinbase fee" of $19.18, which is 4.0%(!). Let's say you buy, the price of Bitcoin goes up 10%, and then you sell. You end up paying 9% round-trip, locking in at most 1%. Coinbase gets 90% of your profit and you take 100% of the risk. Not optimal.
A better option is to fund from your US bank account, but you will still pay 1.5%. So in the example above, Coinbase keeps 40% of your profit.
All of this is disclosed in the fine print on their website, but not always obvious to the average trader.
Sometimes companies offer an "easy" option, which sounds nice. It's just a way to identify the suckers, provide limited transparency, then gouge them on price. Many exchanges and vendors offer a basic version for "everyone" and a pro platform for "advanced traders". The differentiator is usually just price. And you probably know this already, but definitely don't pay via credit card.
This is just as easy as using Coinbase, just with more data and charts that you can just ignore if you want. In the previous example, you would pay $8718.00 (instead of $8761.38) and the spread between bids and asks is $0.01. The quoted fee is $2.50, which is 0.50%. Cheaper than 4.5% or 2% and a hell of a lot more transparent. On both platforms, all you need to do is fund the account, choose buy/sell, and specify an investment amount. Now if Bitcoin goes up 10% and you sell, Coinbase has taken 10% of your profits instead of 90%. Better, but still not ideal.
Be careful about the quoted price. It might be the best price from an exchange order book or it might reflect a, sometimes massive, price markup. These markups are usually not disclosed in an obvious or transparent way.
Coinbase Pro is a great platform, but it's only one source of liquidity. Sometimes different exchanges can have better prices. And most other exchanges have fees lower than 0.50%. Exchanges sometimes advertise a low fee, but you'll note in the fine print that the fee is much higher for small traders, so be careful.
In order to get the best price in the market, it's a good idea to consider opening multiple exchange accounts and/or using a price aggregation tool like CoveTrader (where default exchange fees can be viewed in Settings).
Fees matter and price can vary. It's really easy to get a better deal with just a little research and effort.
CoveTrader by Cove Markets is a platform for active traders of bitcoin and other cryptocurrencies. The crypto market is highly fragmented with dozens of exchanges and limited availability of trading tools. CoveTrader ties the market together in one powerful and transparent trading and analytics platform.