[Ethereum] Reclaim Ether from Fail / Cancelled transaction

For cryptocurrency wallets, you have four choices:

Web-based wallet: Which is what you have with Coinbase; they have the keys for you and make things easier for you (as you don't have to install anything locally). Coinbase does have the option of a "Vault" which adds more control back to you if you're concerned about them handling your private keys, though it's currently only for Bitcoin assets, so not useful for your Ether.

Full Local wallet: That would be like the Mist wallet/browser; you install it locally and interact with it on your desktop. It's more secure since you have the keys locally, and you get a copy of the blockchain locally, so you can interact with it directly. Downside is that the blockchain does take up a fair chunk of hard drive space.

Lite Local wallet: You don't need to have the whole blockchain just to transfer Ether around. Installing a lite client like Jaxx would allow you to transfer your funds from Coinbase to your local wallet, but you're then trusting Jaxx's Ethereum nodes to communicate with. You have more control over your private key, but it's still trusting a third-party.

Hardware wallet: A TREZOR- or Ledger-type device is the most secure in terms of keeping your private key safe, though you then need to use their applications or a web-based wallet that can interact with them (like MyEtherWallet.com) to use your funds.

So, if you're concerned about Coinbase having your private keys, you can either pick another web-based wallet provider that you trust more (generate a wallet on MyEtherWallet, or install MetaMask), or use a local client, or purchase a hardware wallet.

My general recommendation is to use different wallets when the value of what you're saving increases. Aside from the advice to never invest more than you could risk losing, I'd say using a local wallet (lite wallet app on phone or laptop) for "pocket change" daily spending currency, and a hardware wallet for long-term savings is a good route to go. Web-based wallets are okay for special uses (exchanges, etc.), but shouldn't be storing the majority of your funds.

From Bittrex FAQ

Deposits - Please be aware that some coins require us to move your funds to another address before we credit them. This means the coins network will charge you the normal transaction fee for this send. This is not something we can avoid.

You can read here for a breakdown of why you have been charged that fee, as follows,

So the way bittrex eth wallets work is that they have you send money to the wallet and then they move the money to the bittrex wallet via a smart contract. So that's already 2 transactions. An ethereum simple transaction costs 21000 gas and at 70 Gwei gas price, which is high (normal is 20GWei), that comes to 0.00147 ether for the first transaction. The second transaction is sent to a smart contract, which can tell the difference between ETH and ETC, so it is a little more expensive to run, but also the cost is indeterminate, so they reserved 135546 for gas for the transaction, but only used 34470. The transaction cost 0.00258525 Ether based on gas price of 75 GWei. The reserved (unused) gas is still in the bittrex wallet ((135546 - 34470) * 75 GWei = 0.0075807). which accounts for all of the missing ether. Fortunately, the 0.0075807 is still yours, but you need to contribute more to the wallet to get it. The flat cost of contributing any amount of ETH will be about 21000 * first gas price + 34470 * second gas price ether, and there will always be an unclaimable amount around 101076 * second gas price ether. I see the same thing for my contributions (albeit I had a lower gas price). The higher the gas price, the faster it actually gets processed, so the exchanges keep them high and adapt to the size of pending transactions. That all means that if you contribute small amounts of ether, you are gonna pay 5%+ and if you contribute large amounts, you will see trivial amounts of ether missing.