Outsourcing is soooo much fun. You wish to save money while transferring wealth to the needy.
You'll hire 10 employees full-time in PH or India. You'll spend a long month on recruitment. Then at least 1 week on training. 

You need a FT team leader to supervise ongoing, because those ol' era Upwork employee screen capture activity spy monitors are a Useless PITA.
And if remote workers are not monitored every sec, they work for others while billing you. Or watch Porn on their phone.

Oh, and make sure the team know the difference between an Opt-In form to a contact form.
And how to find the contact forms. Because some sites don't have one and some hide it.

And will they submit your text and the 'from email' when Copy & Pasting
- without screwing it up, like missing a letter from your email address, or worse?
Humans make errors. Happens all the time.
Esp when bored, tired of the factory work or forced to speed up.

Rough estimate: 10 x $500/mo [at least]  +  $6,300/mo [$35/h for team leader with brains & integrity and let's hope he's never ill]
= $11,300/mo not to mention your HR hiring month and that cost. 
(Probably half will be bad eggs and the hiring game and cost will repeat).

Then there's also the costs of a double-pay Christmas month and paid holidays, sick days and loads of bad weather calamity days.
Lots of Hurricanes, typhoons, floods and earthquakes in South-East Asia. Power failures. All need to factored into costs. 

If we're optimistic and hopeful, in a month the 10 can submit to 50k contact forms. 
After (at least) 24 months of sifting through 2,000,000 Shopify sites they found 850k sites.
Well, much less actually, since many hide or remove their forms.
 And your team won't be able to contact the 65% site owner we can reach.

So where are we cost-wise? 24 long months @ $288,000. That's where.

Oh no, now you discovered they get blocked after submitting 100 forms.
So you'll need to pay a BPO center double to get it done. 
IF they know what to do and can do it at scale.