I'm probably worrying a bit too much about this, but how long does it generally take to receive a NOA1 for the I-130? I submitted mine almost 3 weeks ago and haven't gotten anything yet.

I did not mail it from within the US, which I'd imagine takes a bit longer. I'm kicking myself now for not choosing a faster shipping option.

About 2 weeks from when they receive it.
Also, note that the NOA1 printer must have run out of ink, because I know there were problems with some people getting the NOA1 form, but they were in fact already in the system.

If you paid by check, just watch for your check to clear the bank.

On the back of the check will be your case number.
I believe all cases are going to California now, so it will begin with WAC

Usually it used to take a week to ten days. But that has not applied since early April of this year. First, they were slow with opening and inputting the I129Fs and I130s because of the deluge of H1B petitions. Then there were CSC computer and printing errors, plenty to make sure that people have not been getting their NOA1s as timely as before. Some didn't even get one at all. But it has gotten better.

It takes forever and a day nowdays. Look at my timeline.