Head to TKTS
The classic way to find deeply discounted tickets is to wait in line, on the day of the show, at TDF’s TKTS Booth under the red steps in Duffy Square (47th Street and Broadway). All but the biggest Broadway hits are on sale there, mostly at 50 percent off. If you are not looking to see a musical, the Times Square booth has a "Play Express" window that will cut down your wait time. The Times Square TKTS Booth is open every day of the week, starting at 3pm for evening performances and 11am for matinees (on Wednesdays, Thursdays and weekends). You can buy tickets to either same-day performances or next-day matinee performances.
In addition to its flagship Times Square location, TDF operates another booth at Lincoln Center’s David Rubenstein Atrium (Broadway at 62nd Street), which opened in 2016. It’s only 15 blocks from the main booth but it’s far less crowded—and it’s indoors, which is a big plus in inclement weather. The Lincoln Center outpost is open from 11am every day except Sunday and Monday.
As a general rule, the earlier you get to TKTS the better, but blocks of good seats are sometimes released closer to curtain time. To see what is available on a given day, download the TKTS app or visit its website. You can buy up to six tickets per person at a time; there is $5–$6 fee per ticket, which is substantially lower than the fees on most ticketing websites.