This past weekend we saw the delightful MIDSUMMER for £15 a ticket (unreserved) and a superb concert by the BBC Symphony led by the charismatic John Wilson for £12.80 a ticket (orchestra stalls seats). This week I will see Derek Jacobi in KING LEAR for £18 (front row circle), a critically acclaimed revival of THE GLASS MENAGERIE for £10 (front row orchestra stalls) and a revival of a Graham Greene play for £9 (unreserved). That's £65 pounds (a little over $100) for five performances. An orchestra seat for a Broadway show is upwards of $135 before all those handling fees are added on ($75 or so for Off-Broadway and non-profit theaters). This means that theater is affordable, not much more expensive than going to a movie. Granted, none of the productions I saw last week or are seeing this week are West End commercial productions which are considerably more expensive, but seldom as interesting as what is running off West End or on the fringe. They now have a top of around £60 a ticket (around $96 which is still $40 cheaper than Broadway). But one can see a lot of great theater without going to the West End. One goes there for big stars and big musicals.
My point is that one can go to the theater regularly in London. It needn't be a special occasion. This means that one feels more adventurous. I will gamble on a new play at £10-£20 a ticket. I would be unlikely to do so at $135 a ticket. Here the level of acting is so consistently high that you are likely to get as good, if not better, performances on the fringe as on the West End.
I don't include the Royal National Theatre in my argument. Their productions are usually excellent, though they seldom get the best of the new plays. As a national theater, it should be affordable, but except for the discounted summer productions in the largest of the theaters, their prices are inching close to those on the West End. Under 25s can get in relatively cheaply and over 60s get a deal on the weekday matinees but with a £44 top, you don't gamble on National productions unless it is something you feel you must see.
Like New York, there is a half price ticket booth and on weekdays most shows are available. I have noticed that a lot of shows are no longer offering half price tickets, but something like 2/3 or 3/4 price tickets.
The point of all this is -- if you are a theater fan and want to glut on theater, London is the place to be.