Which wifi shield should I buy ?

Hello my friends;

I am curently working on my project which is measuring current and voltage with ACS712 and voltage devidor and sent data thew WIFI.

Okej so I understand how to use sensors and measuring but I don't know which wifi shield module should I buy to work with. There are so many of them.

I am looking for the easiest way, so just plugging it and triing to connect ( "withour flashing wifi module or something")

So may someone of you help me and maybe send me some ebay links which module should I buy and how to program it.

Thank you, fellow