I will be in New York in October and would like to see Aida and Les Mis. What are my chances of finding half price tickets at the TIKTS? Thank you

Quite good. Both have been playing for ever and are no longer "hot."

The website below lists what is on TKTS Monday-Friday after 4:30pm. You may want to monitor it for a few days and see if your shows pop up.

http://newyork.citysearch.com/feature/34843/

If you want to buy discounted tickets in advance (either by phone/web or in person once you get here) check out the promotions offered by the NYC tourism office


Aida at $60
http://www.ilovenytheater.com/aida_01.html

Les Mis at $45 (1/2 price)
http://www.ilovenytheater.com/aida_01.html

About 15 shows are listed here at 20-50% off (including new shows Flower Drum Song and Hollywood Arms)and the deal is good through October 31st.
Of course, no Producers, Lion King, Mamma Mia, Hairspray....

Discount codes for both shows available through www.playbill.com..by signing up (no cost) at the online theater club.
The great advantage is that you can avoid standing on line at Tkts and you can choose from available seats when you purchase online. Enjoy!

You've gotten good advice so far. While you pay a little more getting tickets in advance as suggested, you save time by not having to wait in the TKTS line.
If you want to save the $6-per-ticket service charge ordering in advance, you can run off a copy of the Playbill offers and take them to the box office when you arrive.
Les Miz will definitely be available at TKTS, while there's a good chance for Aida, especially midweek performances.