I hope I don't run into this problem. I just downloaded Avast on two of my computers and it prompted me to delete previous free antivirus programs which never tried to "force" me to purchased a paid version. 
Avast doesn't force you to purchase their paid product. I've use their free product since 2003 and am still using the free version.
Only one resident AV. You need to totally remove any others before installing avast.
Did you have to constantly uninstall then install to keep using the free product? Also by "Only one resident AV" do you mean I can only be running the free version on one computer and will have to delete the other AV running on my second computer?
No you don't constantly have to uninstall read all of this topic and you will see it isn't normal, but a problem with the new licensing function. In over 13 years of using avast I have never had to uninstall and reinstall avast free to register again, this is a recent issue.
You shouldn't have two resident (on-access) AVs installed at the same time, there is a strong chance that they will conflict. If you want Avast free on your other system then you would have to uninstall the current AV first.
