Have you written to the site owner with that suggestion? You never know until you ask what might happen. Use the link at the bottom of the page that says "contact us" and I'm sure she will get back to you quickly. Whether or not she can offer a monthly subscription remains to be seen, but it can't hurt to ask, right?
I am the same but love all the freebies. lets see what can be done, it would be great to get by the month subscription