Are 3 payg sim cards available for Lumia 820 yet ????

I don't know what you are asking for specifically but the Lumia 820 takes Micro sims which three do provide (I used my Lumia 820 on three for a year before moving to Tesco mobile)
 
With SIM card cutters and adapters you can use pretty much any SIM card in any phone.
 
yep, i have the "3" 1-2-3 payg sim (bought off ebay and not cut down) in my work phone and works excellent....H H+ pretty much everywhere,the best signal out of all the networks!
 
I rung them up and asked them at 3,
They said it wouldn't work in my area as yet, but they've sent us 2 out,
So I'll maybe give them a try in it anyway.....