Hi Breno,
I have someone interested only in the altimeter and pulse meter. I bought these items to control the quality and time needed to go to altitude, but they are not mandatory. I came to the following observations:
Getting to altitude: (4000m)
tent: 1h00-1h30
head tent: 20min
The machine is quite precise and so I would recommend you only buy the system and a cheaper oximeter on amazon for instance http://www.amazon.com/s/ref=nb_sb_ss_sc_0_7?url=search-alias%3Daps&field-keywords=pulse+meter&sprefix=pulseme%2Caps%2C206
The oximeter is useful for initial training to know the adaptations on you body and when you can increase or need to decrease altitude stimulation.
I could drop the price to 2650US if you can buy the system only with tents and I could drive halfway as well to meet up.
Let me know
JM