Sizzy is having a “Birthday Sale” at the moment!
They offer “50% lifetime discount on any plan”.
(I don’t know how long this offer will be available).
The “Solo Plan” license (for one computer), is now $30 (a year), instead of $60.
And the 50% discount is recurring each following year!
There is a 14 day trial, so you can try before you pay.
See their site for info about the other plans (Trio and Team) for 3 or 10 computers.
Which are also offered now with the 50% discount.
Sizzy is a responsive browser tool, to see and test your website/project for different device and window sizes (different viewports).