Retargeting Pixel

Looking to purchase a simple retargeting pixel that simply captures the e-mail address of users who come to my website. I can then run facebook ads to that list of e-mails with a custom audience.. I know facebook has their own retargeting pixel but that won't work. I also don't want to use adroll or similar service that charges thousands of dollars, they have tons of features I do not need to use, looking for a very simple pixel, don't need all the bells and whissles those services provide. Can anyone provide any info. on this?