For the past 2 months I've been running two linode instances as pool severs. tick.no-such-agency.net and tock.no-such-agency.net.
They are the smallest instances linode offers 1cpu, 1TB transfer, 1G ram and cost $5 a month each, running ntpsec. I've got both of them set to 1G for both IP4 and IP6. So far I'm seeing about 550GB/month of traffic on each node. Pretty good stability and accuracy (unlike the Digital Ocean nodes I tried which had +/- 100ms excursions).
I've been very pleased with the results, for $120 a year I'm adding a lot of capacity to the pool (plus I'm using them for monitoring some work stuff so really the pool use isn't costing anything I wasn't already spending).
A few interesting observations. IPv4 traffic is fairly steady at 1.5 Mb/sec with a minimal time of day component to the traffic volume. IPv6 traffic varies on a 24hr cycle, dropping by 50% at around 08:00 UTC and peaking between 22:00 and 02:00 UTC. However IPv6 volume is a fraction of IPv4, averaging only 200Kb/sec.
CPU utilisation on the small instance at the current traffic level is ~20%.
No significant difference between the east and west coast servers in terms of traffic.
Overall traffic grew almost immediately with speed changes and then climbed ~10% over the first month and less than 5% in the second.