If i go to USA, how common is it to see a preacher on the streets

[Fidel_Castronaut]

Another Brit here;
Street Preachers aren't all that predictable, (at least from the outside) though there are some general patterns.
In Manchester you'll most likely find one in Exchange Square, in Liverpool it's Bold Street or Church Street, In Chester it's Eastgate Street.
They are far less common away from city centres but there are exceptions to that. Llandudno apparently have a team of wannabe missionaries working the North Shore Promenade.

I never see them in the suburbs of British cities (that I'm familiar with anyway).

But into the centres and you see them quite often. By the main train station in Birmingham there's always an Islamic stand with Muslims trying to peddle the Quran.

And even some hare krishna's too.