Which booking tools work?
Any that gives you a link: the signature just links to your booking page.
Does it track when people open my emails?
No. There is no tracking pixel in any signature. Clicks on your signature's own links are counted, and that can be switched off on your dashboard.
What do recipients using Outlook see?
Current Outlook plays the animation unless animation effects are switched off in Windows; older versions show the first frame. Every design starts on its finished frame, so either way they see a complete signature.
How much does it cost?
Your first month is free, with no card needed. After that it is £2.99 a month or £29.99 a year in the UK, €2.99 or €29.99 where the euro is the currency, and US$2.99 or US$29.99 everywhere else, with tax included, and you can cancel at any time.