Not everything is costly. For instance a wordpress.com is free and takes unlimited traffic but your own wordpress instance costs money and has limited traffic.
As a person who has front paged multiple times on HN, I can tell you my blog is self hosted WordPress on a $10/mo digital ocean droplet, and it has fared very well every single time, including almost 100k views in a single day. I'm pretty sure if my $10 stock instance can handle the traffic, WordPress.com can definitely.
