Found the following hamletworks.org entries referring to line 301
View Commentary Note for 300
300
Quee. Let not thy mother loose her prayers Hamlet,
1.2.118
View Commentary Note for 301
301
I
{pray thee}
<prythee>
stay with vs, goe not to Wittenberg.
1.2.119
View Immaterial Textual Note for 301
301
I
{pray thee}
<prythee>
stay with vs, goe not to Wittenberg.
1.2.119
View Material Textual Note for 301
301
I
{pray thee}
<prythee>
stay with vs, goe not to Wittenberg.
1.2.119