Both have the same free tier and both are possible of course. In this particular example it’s SendinBlue.
Bubble integrated Sendgrid, check out this thread [New Feature] Using Sendgrid for emails
Thanks,
Levon.
Founder at Bubblewits - Bubble Certified Partner
http://bubblestore.io – a place to buy Bubble templates for landing pages, e-commerce, workflows, APIs etc.
http://iambubble.com - one page Bubble demo
http://builtonbubble.com - Collection of apps built on Bubble