Namaste
Here is an e-text of basic sUtras with their anuvRttis. [They say- some anuvRttis are misdone, but mostly it is OK.]
The blue part is the basic sUtra. Rest of the colours are anuvRttis.
Here are sUtras with hyperlinks to their Samskrt commentaries. Click the sUtra and get the commentary page.
Something similar as above- but all Samskrt commentaries within same page. Page might take sometime loading. You can use Ctrl+F for particular sUtra.
4. Best way to get hard copies of books is checking with online catalogues of Samskrt publishers, getting them puchased online.. or they can send the required on phone calls on VPP payment as well.
Ashtadhyayi sUtrapATha best edition is
अष्टाध्यायी सूत्रपाठः,
Editor- स्वामी प्रल्हालदगिरि,
Publishers- कृष्णदास अकादमी, वाराणसी. Series- 65,
Year -2001,
Cost- Rs. 45.
If you want with commentaries, then many questions follow- about language, method etc.
Hope this helps. All the best.
-ushA