Send 0.01 BTC without a fee?

[SgtSpike]

Is it possible to send someone a bitcent without a fee?  How old would the coins have to be in order to do so?

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[Blazr]

Its possible, but it won't always get confirmed.

I only send a 1 satoshi tx fee for all of my transactions (regardless of size), and I've yet to get one that didn't confirm. I did have a few that took a few hours to get 1 confirm though.

There are miners out there that will accept transactions that haven't paid the minimum tx fee.

[FreeMoney]

Its possible, but it won't always get confirmed.

I only send a 1 satoshi tx fee for all of my transactions (regardless of size), and I've yet to get one that didn't confirm. I did have a few that took a few hours to get 1 confirm though.

There are miners out there that will accept transactions that haven't paid the minimum tx fee.

Are you sending the tx direct to pools?

[SgtSpike]

Its possible, but it won't always get confirmed.

I only send a 1 satoshi tx fee for all of my transactions (regardless of size), and I've yet to get one that didn't confirm. I did have a few that took a few hours to get 1 confirm though.

There are miners out there that will accept transactions that haven't paid the minimum tx fee.

Are you sending the tx direct to pools?

Mainly, I was curious if a site that gives away free small amounts of BTC could potentially send those amounts as soon as they are requested instead of waiting to send them all in one big batch.

[Kansattica]

You can always send without a fee, sometimes it'll take forever. Sometimes, though, I'll be using the wallet at Blockchain.info and it won't even ask me to include a fee. I believe the bitcoin protocol codes for something like 50 KB of free transactions per block or something.

[Blazr]

Are you sending the tx direct to pools?

Nope. I'm broadcasting them just like any regular tx. Haven't targeted any pools. They usually take around 20minutes to get a confirm, but occasionally take much longer.

[dooglus]

Is it possible to send someone a bitcent without a fee?  How old would the coins have to be in order to do so?

To avoid fees, the coins you spend should be at least 1 "bitcoin day" old.  A 3 BTC input that is 4 days old is 12 "bitcoin days" old.  Like "man hours" - 3 men working for 4 hours each is 12 man hours.

So to send 1/100th of a bitcoin for free, it needs to be 100 days old.

To send 24 bitcoins for free, they need to be 1 hour old.

Etc.

If any of your outputs are less than 0.01 BTC (including any change output), then you will always need to include a fee.

This is to avoid the recommended fee, of course.  If you edit the source you can send any amount you like without a fee, but miners may then decide not to include your transaction in a block.

Edit: if you have a 1 BTC coin that is 1 day old, you will be able to send 0.01 BTC (with 0.99 BTC change) without paying a fee.  It's the size and age of the inputs that matters, not the outputs.  Though the outputs have to be a bit cent or more to avoid fees.

Edit2: and it's not really the age that matters, but the number of confirmations.  If we get 1 block every 10 minutes then the above is true.

[Stephen Gornick]

And if you look at this site, you'll see no red ("no fee") transactions that low that confirmed anytime soon -- regardless of age.

 - http://bitcoinstats.org

[SgtSpike]

Is it possible to send someone a bitcent without a fee?  How old would the coins have to be in order to do so?

To avoid fees, the coins you spend should be at least 1 "bitcoin day" old.  A 3 BTC input that is 4 days old is 12 "bitcoin days" old.  Like "man hours" - 3 men working for 4 hours each is 12 man hours.

So to send 1/100th of a bitcoin for free, it needs to be 100 days old.

To send 24 bitcoins for free, they need to be 1 hour old.

Etc.

If any of your outputs are less than 0.01 BTC (including any change output), then you will always need to include a fee.

This is to avoid the recommended fee, of course.  If you edit the source you can send any amount you like without a fee, but miners may then decide not to include your transaction in a block.

Edit: if you have a 1 BTC coin that is 1 day old, you will be able to send 0.01 BTC (with 0.99 BTC change) without paying a fee.  It's the size and age of the inputs that matters, not the outputs.  Though the outputs have to be a bit cent or more to avoid fees.

Edit2: and it's not really the age that matters, but the number of confirmations.  If we get 1 block every 10 minutes then the above is true.

I just realized though... in order to make it work, one would have to "pre-send" a whole bunch of 0.01 BTC amounts to different addresses.  That way, the coinage not sent remains old.  If I were to just send 0.01 out of 1 BTC, then suddenly, the other 0.99 BTC is brand new again, and cannot be sent fee-less for a while afterward.

Thanks for the input Blazr - I was looking for more of a technical response about when a fee is required/not required, but it's good to know that even though the fee is "required", it still eventually gets pushed through.

[Stephen Gornick]

I was looking for more of a technical response about when a fee is required/not required

There's good info here:

 - http://bitcoin.stackexchange.com/questions/3400
 - http://bitcoin.stackexchange.com/q/1261/153

[dooglus]

I just realized though... in order to make it work, one would have to "pre-send" a whole bunch of 0.01 BTC amounts to different addresses.  That way, the coinage not sent remains old.  If I were to just send 0.01 out of 1 BTC, then suddenly, the other 0.99 BTC is brand new again, and cannot be sent fee-less for a while afterward.

That's right.  You would have to wait another 1.01 or so days before you could use the change 0.99 BTC without incurring a fee.

But remember, if you pre-send 0.01 to yourself 100 times (you can use the same address for each - they'll remain as separate inputs as far as the network is concerned) you'll have to wait 100 days before spending any of them.

You might decide it's better to pre-send 0.10 to yourself 10 times, and then only have to wait 10 days to be able to spend them.  Or maybe send a range of different sizes to yourself, which will then 'mature' at different times.

Unfortunately the satoshi client doesn't make an effort to try to pick inputs that will avoid transaction fees (other than to prefer inputs with 6 or more confirmations over those with less), so you'll likely end up incurring fees unless you patch the client to allow you to manually select which inputs to spend.  There's a pending pull request ('coin control') which allows you to select which addresses to send from, but it doesn't allow control over individual inputs if you have multiple inputs at a single address.

[pc]

The other odd thing you can do if you have a big enough wallet is to add on a payment to yourself to make the transaction have more BTC and so require less time to go through without a fee. For example, if you have say over 100 BTC, you can make a bunch of 0.01 BTC payments just about whenever you want, as long as in the same transaction (using sendmany or the "Add more" button of Bitcoin-qt) you also add on a 100 BTC payment to yourself. That makes the number of bitcoin-days in the inputs much larger.

It's things like that that make me think that the built-in fee rules may encourage transaction spam in some cases rather than discourage it, though I must admit that I don't particularly have a better algorithm to propose.

(And as others have said, you can modify your client to propose a different fee structure, and some miners may be running under a non-default fee structure as well.)