Can I limit my tickets sold per buyer?

I'd like to limit certain tickets sales to two per customer.

You can add a quantity property to your product and limit it to 2 and then enable the unique question option by going to Preferences and choosing which field do you want to setup as unique:

This way they only accept one submission with that value (it can be name, ID, ...)

You can try and clone this test form:

http://form.jotformpro.com/form/41184193267962

Please try to submit the same name 2 times.

Let us know if we can be of assistance.