Whilst these add ons are available for free, they cost the developers real money to make. Websites and bandwidth are not free, neither is the computer equipment used to make these downloads.
I'd really appreciate if you could spare the money for a donation. £1.50 is the price of a single journey on the London Underground network, and you can donate as many "journeys" as you like. It's extremely unlikely developers will ever break every small donation will go towards creating more content and covering website costs.
You can also donate by sending a PayPal payment to email@example.com.