I just completed one task of my personal bucket list some weeks ago!
I took the train to Budapest and listened to Mahlers 8th symphony in the state opera. It was a wonderful evening! The day after, we had a look at your beautiful city. It was my first time in Budapest, but definetly not the last one! But I guess, that it was a rare exception (a normal concert in the state opera). Or are there similar concerts sometimes?
There used to be 10 concerts a season in the Opera. My first concert was there in April 2014. The tickets & season tickets were dirt-cheap.
If You interested in orchestral concerts, I suggest buying a ticket to BFO, Hungarian National PO, Hungarian Radio SO or MÁV SO next time. I can help with HRSO tickets as I pay 800HUF per concerts, and I also can help in Hungarian National PO tickets, I bought tickets for 1500HUF in September. Most orchestral concerts are in Liszt Academy or Müpa, I prefer Liszt Academy. Pannon PO gave a concert a couple days ago in Musikverein, but the best seats were 80€ instead of 20€ (Müpa prices).
Today I had the opportunity to
book for December 3rd or 4th BFO concert for 1800HUF. This wasn't in my season pass.
(Carl Maria von Weber: Oberon – Overture, Grieg: Piano Concerto in A minor, Tchaikovsky: Symphony No. 5 with Andrés Orozco-Estrada & Javier Perianes.)