Are server transfers ever free?
https://wiki.guildwars2.com/wiki/World#Transferring
About the second question, it’s account wide.
It’s only free if you delete all your chars. If an account has no chars it gets the option to change servers. ANet does occasionally decrease the prices on the lower population or lower tier servers, usually when there is a tournament for WvW.
ANet may give it to you.
I do recall one short time frame before one of the WvW seasons started where they altered the “pricing” to transfer in an attempt to encourage a server population balancing:
FULL / VERY HIGH population servers were 150% normal cost
HIGH population servers were normal price.
MEDIUM servers were 50% normal
LOW population servers were FREE.
Since they haven’t done this again (that I’m aware of), I don’t think it improved the server population balancing at all.
Fate is just the weight of circumstances
That’s the way that lady luck dances
Sadly those transfers are rare. Maybe around the WvW season comes but that might be a while. I havent seen the free transfer since a 2 years ago If I remember correctly. That was more in regards when they tried to figure balance with WvW populations.