Gracias, but.......
No, I do not wish to visit a time-share seminar.
No, I do not want to go to any tourist activities.
No, I do not want to take $150 from you, for any promocion.
I did all this last time.

If I want to do anything, I will surely ask you.

Gracias

(I plan to have this printed on a T-shirt before I go to Mexico next time)