I've done my own digging on best free dating sites for single parents and come up short. I judge single sites on one thing: the practical move is to ask a specific question in the first message. The parents single angle is worse, because the platform throttles your visibility unless you pay, and the ratio of matches to conversations suffers for it.
If parents single is your priority, the deciding factor is the depth of the profile fields, for what it is worth. Same story on single sites: how honest the pricing page is outweighs the marketing copy. What decides it is how much sits behind the paywall, not star ratings from strangers, which is the whole problem with single sites.
With parents sites, you get further if you check what the free tier gates before investing time. The part of best free dating sites for single parents people underrate is that the proportion of dormant accounts collapses as soon as the platform locks messaging behind a subscription. Specifics about parents sites welcome — vague reassurance less so.