Building a business on blank cheques and accidental spends is shady. It's also a large barrier to adoption. The more times devs see reports like, "I tried [random 20-minute tutorial] and woke up to a bill for my life's savings and luckily support waived the fee this one time but next time they're coming for my house", the less they'll want to explore your offerings.
e.g. for me. I never dared to get my foot wet with AWS, despite interest. Better safe with a cheap, flat-rate VPS than sorry.
I also have an account with L̵i̵n̵u̵x̵A̵c̵a̵d̵e̵m̵y̵ A̵C̵l̵o̵u̵d̵G̵u̵r̵u̵ PluralSight: and while the courses are very variable (and mostly exam cramming focused) it has their Cloud Playground as a super nice feature.
I get four hours to play around with setting things up and then it will all get automatically torn down for me. There's no cloud bill, just my subscription (I think that's about $400pa at the moment - can't check right now as annoyingly their stuff is blocked by our corporate network!) It has a few limitations, but none that have been problems for me with exploring stuff so far.