I’ll be holding a soldering class for some 12 year old children this fall, where I plan to have them solder a Freeduino board, which is Arduino Duemilanove compatible (more or less equal to Arduino Uno as far as I can see).
What is the cheapest and easiest way of getting these boards connected to Blynk Cloud?
Each account starts with 2000 recyclable energy.
But you might want to reconsider the type of board like ESP8266 based… as connecting an UNO type board to the internet requires additional networking components, proper power distribution, communication wiring, setup, etc.
Or you can use USB connection option
Yes, I was including that in the mix… just not getting into specifics until further OP feedback 
Also that method really requires each student or two have a PC, and TTL-Serial adapter for diagnosis,.of their own for such runtime use
ESP8266 would be easy connection-wise, but not so easy to solder. Need a board with through-hole components.
PC’s wouldn’t be a problem. It’s normal for each pupil in Norwegian schools to have their own computer. Also, the solder class is a part of Girl Tech Fest, an event consisting of classes in Python, Scratch, MicroBit, etc., to try to get more girls into engineering jobs.
Perfect then… USB-link will then require the least additional hardware.
http://help.blynk.cc/how-to-connect-different-hardware-with-blynk/arduino/usb-serial
Excellent! This is exactly what I need. Thanks to the both of you.
I ran exclusively on USB-link for the first 6-8 months of using Blynk. Didn’t even own an ESP8266 for what seemed forever 