It could be emptied out after 400 coins, not 900. If there is already money in there it would take a little more, not much. Unless my math is wrong.
https://news.ycombinator.com/item?id=16226641Reproduced here with more columns, assuming initial price of .02 ETH per coin:
+----------+----------+-----------+------------+-------------+
| numCoins | coinCost | coinValue | sell price | Profit/Loss |
+----------+----------+-----------+------------+-------------+
| 100 | 2 | 0.01 | 1 | -1 |
| 200 | 6 | 0.02 | 4 | -2 |
| 300 | 14 | 0.04 | 12 | -2 |
| 400 | 30 | 0.08 | 32 | 2 |
| 500 | 62 | 0.16 | 80 | 18 |
| 600 | 126 | 0.32 | 192 | 66 |
| 700 | 254 | 0.64 | 448 | 194 |
| 800 | 510 | 1.28 | 1024 | 514 |
| 900 | 1022 | 2.56 | 2304 | 1282 |
| 1000 | 2046 | 5.12 | 5120 | 3074 |
+----------+----------+-----------+------------+-------------+
Also the guy said he has 200 coins to use whenever he wants
