Alfredo, mi hermano
How small is the area you want to fly in?
With a 40 size trainer i think you might need something like 30mts wide and 100mts long to have somewhat comfortable landings.
Also i have a friend in Guadalajara (i'm from Merida), his name is Juan Carlos Alcocer he is a VERY GOOD instructor, very kind and patient, and he will provide you with a trainer for you to learn on, very cheap also, about $50 MXP (less than US $5 ) for half an hour or something like that, if you crash his airplane you don't pay anything, his philosophy is that if you crash while he is teaching you on a buddy box, it's his fault (and he is right :P) he can also get a second hand trainer for you, cheap, just while you save some money to buy a new one.
My only DIRECT experience with the guy comes from buying stuff from him, he was not my instructor, but i have several friends in guadalajara who shared their experiences with me and i'm passing them on to you.
I don't know haw far is Chapala from Guadalajara, but i think you might wanna pay him a visit on a weekend
Give me a private message and i'll give you the details of his hobby shop so you can contact him if you're interested
Alfredo, habrán ocasiones en las que te desiluciones y tengas ganas de renunciar al hobby, pero hay MUCHISIMAS satisfacciones esperando por ti, no renuncies NUNCA
Saludos desde Mérida