I second the advice to get the washable ones for long term use. I still have disposable ones but since I'm in Germany I can't be any help in where to buy them

We just got our washable ones from Little Bit on here. There are sooo much better at least for Walker. No shredding. He goes on them versus putting his front feet on them and peeing next to them. I don't need to change them every two pees so one pad lasts the entire day. They are a little bigger, but I think she does make them to size if you'd like. Good luck and I hope you find some!
Here is her website.
Washable pads