Hi @sebas911 and welcome to the Klaviyo Community!
Users on free plans can definitely create and implement flows. The only limitation will be how many emails you can send. When you hit that threshold, you will be required to upgrade or the flow will stop sending until the following billing cycle. You’ll be able to see how many emails you’ve sent in your Account Settings.
If you’re not seeing people trigger your flow, check that your integration is correctly configured, you are collecting consent, and confirm that people are taking the action or meeting the conditions you set for triggering your flow.
For example, if you are setting up a welcome flow that triggers when someone joins a specified list, confirm that people have joined that list. For a metric-triggered flow, take a look at your analytics tab and filter based on the metric you are using to trigger your flow to confirm that people have taken the action since you set up your flow.
If you are looking for help with a specific flow, please share the details of your flow here so we can help! Details to include are the flow trigger, any flow or trigger filters, what integrations you are using for the flow trigger.