I just email them to my kindle thought. http://www.amazon.com/gp/sendtokindle/email
In terms of the Kindle's ability to handle PDFs, does it allow for resizing the page? Or is it pretty important to get the PDF page sizes "kindle-sized" to have a hope of reading it without a magnifying glass?
In my experience, I've found that the Kindle can convert PDFs pretty well as long as there is extractable text that's not too weirdly formatted (as a cursory test, try viewing a PDF and highlighting words. If you can do it, it's probably okay to convert). Otherwise, it's true that you'll probably run into sizing issues :(
https://ifttt.com/recipes/17578-if-stored-in-kindle-dropbox-...
Kindlebox is a nicer way to do it if that is all someone wants, something I would send to my mom instead of teaching her how to use ifttt.com.
Amazon took me to my country's Amazon site. From there, the snippet button did not work. Also I could not get the precise action behind: "pick your Kindle devices, and you're good to go". So I stopped right there.
The snippet scrapes the Amazon site for information about your Kindle devices. It's possible that it's failing because of different Amazon UIs depending on the country. There should be a message letting you know that it failed.
Make sure you're on the Amazon site when you click the snippet. If it's successful, there should be a list of devices that you "pick" by clicking the names. Once you click the "Activate Kindlebox", that should be it.
Please email me at swang93@mit.edu if you're still having trouble!