I know this does not directly respond to your request for payment by email sent, but here is an alternative.
You can create 5-8x G-suite accounts for 3k per day and send up to 500 emails per day from them.
Here is the warm-up schedule:
Week 1: between 10 to 20 emails per day
Week 2: between 20 to 40 emails per day
Week 3: between 40 to 80 emails per day
Week 4: between 80 to 100 emails per day
Week 5: 200 emails per day
Week 6: 400 emails per day
Week 7: 550 emails per day
Week 8: 700 emails per day
** Lemlist has automatic email warm-up, it costs $ 29 per month if you want to speed up and automate this process **
From here you can use Gmass, lemlist, reply.io 1, etc. to send these emails.
And yes, if you have a good opening rate and a good response rate, you shouldn’t have any problems with sending to the inbox.
But you will have to change your message body once a week, so as not to end up in “message spam”.
I could talk more about that, but I’m just giving you the main details now for you to decide if it’s something that would work for you. Good luck.