Yes, Canva is a free alternative to Placeit. Canva doesn’t have the biggest premade mockup library for Print on Demand sellers but with little design knowledge, the possibilities can be endless. Their partnership with smart mockups has brought them on level grounds with placeit in term of mockups.
Canva offers a similar, if not better, online editor with a faster interface compared to Placeit's. Making it an excellent option for those who want to create designs quickly and efficiently.
While Placeit is more of an entry level tool, Canva is for a bit more advanced users.
Of course, you can easily create simple designs with Canva and easily edit the premade mockup templates they provide but having some design knowledge can take you a long way with Canva.
If you take Canva’s premium subscription, there’s nothing much you can’t do that you can with any other tool available on the market.
Plus, Canva offers many free and paid elements that can be used to make your designs as well.
Canva has video and animation capabilities that can help you to animate any and all designs you make or upload on Canva.
The best part? Even many video and animation capabilities are available for the free users, which is almost rare.
In the end, I must admit, Placeit is an awesome tool with so many premade templates that any beginner Print on Demand seller can just login and make some mockup templates for their products.
But if you are an advanced Print on Demand seller and have a big product library, both Placeit and Canva become almost useless.
For a large number of products, such as the amount that most POD sellers have, Bulk Mockup is the only tool available in the market that caters to that need.
Here is a small demonstration of Bulk Mockup creating more than 400 mockups under 2 minutes so you can understand the power Bulk Mockup provides to Print on Demand sellers.