how many bitcoins did he get for free? 1000?
I would not call it "free". To get a new coin, you had to mine a block, with at least 2^32 leading zeroes. If you do it on your CPU, it is far from free. If your CPU is from 2009 or 2010, then it can take quite long time.
https://www.metzdowd.com/pipermail/cryptography/2009-January/014994.htmlYou can get coins by getting someone to send you some, or turn on
Options->Generate Coins to run a node and generate blocks. I made
the proof-of-work difficulty ridiculously easy to start with, so
for a little while in the beginning a typical PC will be able to
generate coins in just a few hours. It'll get a lot harder when
competition makes the automatic adjustment drive up the difficulty.
Generated coins must wait 120 blocks to mature before they can be
spent.
See? Getting a single block by a single miner was not advertized as "every 10 minutes you will get something", but rather "in just a few hours". And those "few hours" were considered "quick". To generate 1,000 coins, you would need at least 20 blocks. Which means, you wouldn't just magically generate 1k BTC, out of thin air. No, you will start grinding new 80-byte block headers, and after around a week, there is a chance, that you will get that amount.
More than that: if you measure the time between blocks in 2009, then you will get something, which is closer to 15 minutes, than to 10 minutes. Which means, that even the minimal difficulty was considered quite high at that time, because it took a lot of months, to even observe the first difficulty adjustment, when everyone used CPUs to mine blocks.
And it is not all. Even if you got your first 50 BTC "for free" (as you call it), then you cannot immediately move them somewhere else. First, you can see a single confirmation, and you wonder, if your block will be reorged or not. Then, the confirmation counter starts increasing, and you can get your coins 20 hours later (because it was 120 blocks at the very beginning, but later it was changed into 100 blocks). Which means, that you cannot "just get 1000 coins, and move them immediately". No, you have to wait something around 20 hours, to have everything confirmed (100 blocks for coinbase maturity today, and 20 more blocks, if you mined it sequentially). But: if you didn't get a sequence of your blocks, then one block may have 10 confirmations, and another may have 27 confirmations. Which means, that instead of waiting just 100 blocks, you have to wait in practice 200 or 300 blocks, because there are other blocks in between, so your "1000 BTC" is not confirmed all at once, but instead you can see it being confirmed over time.
After a few days, bitcoin was running pretty stably, so I left it running. Those were the days when difficulty was 1, and you could find blocks with a CPU, not even a GPU. I mined several blocks over the next days. But I turned it off because it made my computer run hot, and the fan noise bothered me. In retrospect, I wish I had kept it up longer, but on the other hand I was extraordinarily lucky to be there at the beginning. It's one of those glass half full half empty things.
See? It was definitely not "free". Many CPU miners worried about breaking their computers, because of overheating. And would you risk mining some almost-worthless coin, where for 10k BTC you can buy a pizza? Would you risk damaging your PC for a slice of pizza?
More than that: even today, there are still some places, where you can mine at difficulty one, and successfully get some blocks. For example, testnet3 and testnet4 allow such things. Those coins are worthless by definition, but you can experience it first hand, how many blocks can be mined on your CPU, how long it can take, how many of your blocks may be reorged, how long you have to wait to move your coins somewhere else, and so on.
