22 TB drives are around $230 on ebay, so if you used 15 of them in raidz2, that'd be around $3500 (so maybe a little over $4k with the rest of the server), which is around the cost of a new mirrorless camera and a decent lens, so certainly within the realm of a hobbyist. You probably couldn't get away with downloading 250 TB in any reasonable timeframe with most US ISPs (or at least Comcast) though. That'd be over 2.5 months of 300 Mb/s non-stop. Even copying it from a friend using 2.5 Gbit/s Ethernet would take over a week.