where to find $1 HPT

Lynn • Started ttc in Feb 2016. Started at a fertility clinic in 01/2017! Found out I was pregnant in June 2017! Due 02/2018
Soooo I've been looking around town on where to find the cheapies - I've been to Dollar General and Dollar Tree and neither one had them?! Dollar Tree said they haven't carried them for awhile... 
Where do u all get yours?