What is your workflow for managing leads with a B2C app?

I've been looking into CRMs, but many of them seem to be for more robust B2B needs. My price point is too low to justify spending a lot of time on each lead, but I would like to set up some multi-touch campaigns, automation, and nurturing to move customers through my funnel.

Right now, my data lives in several places (spreadsheets, Mailchimp, database, etc.)

If you have a workflow and example of how you're doing this, that would be great!