What kind of Arduino parts should I purchase in order to send Email?

(Couldn't find an appropriate section for this topic, this was the closest to what I was looking for.)

I have recently decided to make something that sends automated email, and learnt that it required WiFi shield. Once I searched it up, there were too many parts, and I have no idea on what kind of product I should look for.
So can someone give me some basic information on what kind of Arduino parts I should go for, or even pinpoint a product?


(I am using Arduino UNO.)

You could use an ESP8266 board, and no (ATMEL) Arduino at all. I would recommend the Wemos D1 Mini.
This gives you the Wifi connection. HOWEVER, nobody will accept E-Mails that you deliver yourself nowadays. Usually, all IP ranges that are used for home customers are blacklisted by email servers. So you will have to send them via an email server where you have an account.
This, again may be challenging because some services do not accept logins without SSL, which is not that easy on a microcontroller.

You best bet is if you already have an always on machine on your network, connect to that unencrypted and then relay somehow.

Maybe something like http://www.instructables.com/id/ESP8266-GMail-Sender/ . You are probably better off setting up an alternate account due to the need to reduce security.