Hi,
Tell your friend to be very careful. I got burned by a similar offer. Before I knew what was happening they took £75 from my credit card and I am still fighting to get it back.
Back to your cold turkey, I am 9 weeks in vaping so can remember what it was like when I started.
I bought a disposable from Tesco and waited until I got home before using it because it looked huge compared to my rollys and I thought I would look stupid with that drainpipe in my mouth. I was a 40 a day smoker and that evening I only smoked 5 cigs and run the disposable dry. The following morning I was back in town buying a mini kit. 1 battery, 2 cartomisers, usb charger and a cheapo case. I also bought 5 king size menthol carts. By the time I got home and charged the battery I had already smoked more than 20 firesticks but that evening I again used the ecig with an occasional smoker. 5 again.
The following day I was all set and alternating between the two I only smoked 5 real cigs.
By 8pm on the fifth day I lit my 2nd cig of the day and half way through it I thought "why bother". That was my last cigarette.
Nine weeks, four days, 1 hour 57 minutes and counting.
Don't try and make the switch in one. If you feel like a ciggie have one. Next time pick up the ecig and have a few drags. Make it easy on yourself. The day will come when you prefer the ecig.
Phil