The first bikes for both my kids were ridgebacks (honey and melody, 12 and 16″)
Since then have sold them on and replaced with second hand and the cost of each upgrade was made reasonable by the amount I got back for having a decent quality bike to sell on. Now on a 20″ ridgeback, and have just sold a 20″ kona and picking up a second hand spesh 24″ for the elder.
If you get a bso first up, as well as being a less pleasant bike to try to learn on, you won’t enjoy the resale value so you’ll end up spending as much if not more over the long term. If you can’t stretch to the initial outlay, go second hand quality rather than brand new bso, would be my advice.