My dad is a piano tuner now, I'll shoot him a note and see what he recommends for brands. I'm a bit out of the loop but if I remember right, Yamaha, Boston were some pretty good budget pianos.
As for tuning, once a year should be enough, but it depends on the environment it's kept in and how much it's played. If you play more, 6mo intervals are better. Keeping it in a humidity controlled environment will prolong the tuning issues. Changes in humidity will shrink/expand the soundboard causing intonation issues.