If anyone is looking for a solution for this, I've had great success importing data from Google Sheets to Marketo using SyncFrog:
It is plug and play and offers a lot of flexibility at an affordable price. It's great if you are purchasing leads from content syndication -- just set up a sheet and have your vendor paste the data into it. Syncfrog will poll the sheet regularly (up until hourly) and pass the data into Marketo.
Include a campaign reference field and you can send the leads on their way into the right program/campaign. Works great
Tool now seems to be defunct unfortunately.
Awesome...thanks for following up on this. What you described with SyncFrog was exactly what I had set up with itDuzzit. It was awesome for our specific needs.
That said, I just found out a week ago that itDuzzit got acquired by Intuit, so they're shutting down. They provided existing customers with additional alternatives that I'll list here:
Workato provides an enterprise-grade integration platform with an easy-to-use workflow builder that has features similar to the Duzzit Editor and supports cloud-to-cloud integrations.
Zapier is a popular integration automation tool that supports hundreds of popular cloud applications. Their new multi-step zap feature makes Zapier an option for replacing some kinds of custom duzzit flows.
@justin - the syncfrog link redirected to a highly NSFW site. perhaps you can remove it.