Any time a new vendor comes along (free or not) I give them a go if I can fit into my workflow. I use alternative sources to highlight any possible issues on trade signals I'm taking, so I can review prior to placing orders. I can't recommend any of the free ones - they just generate too many false positives of data errors. I also tried IEX - not that good either.
The data may seem good, until it's not. If that causes a missed trade (or erroneous trade) that results in a several hundred or thousands of dollars of loss (or lost opportunity), why would you even bother with free?
I guess if you don't have enough capital to trade then free may be all you can afford. But perhaps it's time to reconsider trading and spend time building up your capital base instead (or alternative career paths).