Yes – once a month you get a free week. Pick a premium skin and you'll be asked "Try a new look for your tree – free for 7 days": press Start my free week and try as many premium skins as you like. The bottom of the Skin list shows how many days are left, and when your next free try is. On day 8 your tree goes back to the skin you had before. The week is yours, not your phone's – signing in on another device doesn't start another one. For example, say Grandad George starts his week on 3 November – his next free try is from 3 December.
Still stuck? Talk to a real person: send us a message, or email support@mywholefamilytree.com