In general a Bitcoin transfaction fee is a market price to get your transaction included in a block. There is one block mined every 10 minutes and each block has enough capacity for a few thousand transactions. You put your transaction out on the network with a fee specified, and miners trying to create blocks can choose whether to include it in the block they attempt to mine. Naturally, miners trying to maximize profit will choose to include the transactions with the highest fees, occupying the least space in the block.
The size of the transaction (in bytes) is not related to the amount being transferred. It is tied to the number of inputs and outputs. Bitcoin doesn't directly track the "balance" of each address. Instead of a transaction saying "deduct 1000 satoshis from my account and give it to Charlie", it says, "take the 800 satoshis received from Alice in this old transaction, and the 500 satoshis received from Bob in that old transaction, and with that 1300 total give 1000 to Charlie and 300 back to me". 2 inputs and 2 outputs in that example, but you can imagine how both the # of inputs and the # of outputs can vary in practical usage. Therefore, a transaction that moves Bitcoins accumulated from many small transactions will be somewhat larger and have a more expensive fee than one that moves Bitcoins that were acquired all at once.
However, don't take this to mean that has an impact on the cost of withdrawing from an exchange: since the exchange doesn't make on-chain transactions for each buy/sell, it doesn't matter whether you bought your Bitcoins a little at a time or all at once for calculating your withdrawal fee. It'll pretty much be a flat fee.
One other thing - you cant even move BTC in or out of Robinhood. Robinhood for crypto is a complete scam right now.
It has a big warning saying to not use it with cash you aren't willing to lose.
This has tended to be true (that it’d go through within a few days), but right now it’s probably largely false.
Assume a small 226 byte transaction (one input and two outputs); at $50,000 per bitcoin, 50¢ is 1000 satoshi, which is about 4.4 satoshi per byte.
Per https://jochen-hoenicke.de/queue/#0,30d, transactions with fees under 5 satoshi per byte were last cleared on February 8 (~8 days ago), and before that last on January 28 (~11 days). (Before that, such transactions stalled for about 12 days in October/November; other than that, it looks like such transactions never stalled for even a week back to the January 2018 craze, to say nothing of 50¢ being more satoshi per byte back then anyway.)
And if your transaction expires after a week——
It turns out that people were right when they said that it would take a long while for it to be adopted.
The miners then choose the transactions they want to include in a way, as to maximize their gains. As a block can only hold a certain amount of transactions and the limit being set by the weight-units [1], miners will want to prioritize the transactions that offer them bigger fees per weight unit, or usually expressed as sats/vbyte (satoshis per virtual bytes).
So if you don't need a transaction to arrive in the next 1-2 hours, you can lower your fees, and the transaction might pass in the night (although BTC is international, congestion is less on US night time and especially week-ends) or if not, probably in the week-end. If it doesn't clear fast enough, or as fast as hoped, then RBF (replace-by-fee) or CPFP (child-pays-for-parent) might help (manually or an increase of the fee could be automated by the wallet every set amount of time).
TL;DR: there is a free market for transactions, but the price is not dictated by the market (and there is no real bidding system), instead you suggest a fee, and see if any miner around the world wants to include it in a block (and you can adjust if the outcome isn't achieved, which has similar results to a bidding system... but is more like natural supply/demand mechanism, as miner do not guarantee to include a transaction).
Helpful to see current unconfirmed transactions (and sats/vbyte): https://jochen-hoenicke.de/queue/#0,30d [info: the legend is clickable, and makes it easier to view how many higher paying transactions there are]
If you buy an option for a barrel of oil, Robinhood doesn't even deliver it to you. Same for wheat and gold. What a scam!
In all seriousness, if you want to speculate on the price of Bitcoin, Robinhood may be better than using some of these more sketchy exchanges that offer decent amounts of leverage.
If you want to actually purchase Bitcoin, there's regulated exchanges where you can do so, though that'll probably land you on some FBI watch list.
Even if the government didn't have that, they might still be able to deanonymize you via your transactions. Pseudonymity is not anonymity. If a single merchant identifies you as the buyer in a transaction, the government might be able to figure out the rest of your transactions in that chain.
I definitely would not call that a scam. I have no reason to move my BTC.
Besides, if you really want to own a given amount of bitcoins that you have in your robinhood account, you just liquidate your position in RH and use those funds to purchase bitcoins directly.
If you're transferring smaller amounts, why are you using Bitcoin? Use Bitcoin Cash or Litecoin or one of these newfangled proof-of-stake currencies. Then it'll be a couple of cents flat.
Power to the people?
The story seems to rapidly shift between "BTC will save Venezuelans from an oppressive government" and "we never said it mattered if people could use BTC for transfers of non-huge amounts of money".
Of course people have trouble pricing Bitcoin, but the same is true for many other assets. If literally the only use for Bitcoin would be to speculate on all the cryptocurrencies, that would be enough to make it valuable.
A wire transfer is a realtime transfer between banks. The only time I've used it was while buying a house. I've never done a wire transfer under $20k.
All free
I'm curious is this the transaction per $100 or is $18 a flat fee regardless of transfer amount?