Marketing Automation Software Recommendations?

Hey hackers,

I'm starting to look into marketing automation for my product, NightCafe Creator.

My goal is to be able to set up an 'abandoned cart' style of campaign, but a little different. Basically if one of my users clicks on a "Buy" button for a certain "creation", I want to add them to a drip campaign convincing them to finish the purchase.

It means the software will need to be able to accept more data than just a subscriber and their name, ideally I'd send a whole JSON payload including the product url, image url, product name, user details, etc - which I can access in the email template.

I'm currently looking at the following:

• Sendgrid ($60/month) - it seems to be pretty bare-bones, but I'm already using it for some transactional emails, and I have a transactional email template I could copy and tweak.
• Mailchimp - probably the cheapest option right now, but seems to get a lot more expensive with more subscribers. I'm also not sure if I could send a JSON payload, I'm not sure how I'd get access to the product information etc.
• Mailer Lite - ($30/month) - the price looks good, but I'm unsure how I'd get access to the product information in my automations.
• SendInBlue - (Looks free until I reach 2000 automation contacts, then $71/month) - No experience with this one, so not sure.

If you've used anything for this in the past, please let me know your thoughts on it. I'm also on a budget, so keep that in mind.

Thanks for your help!