For a pistol, as much as I like Ruger Standards, I have to recommend the Browning Buckmark for two reasons: 1) The barreled receiver is not the "firearm" for the ATF, making barrel changes easier, and 2) Browning has rebates on the Buckmark. $300 will buy a Buckmark. If you do go Ruger, keep an eye on the Volquartsen clearance page at https://volquartsen.com/clearance as Mark IV barreled receivers are being sold for prices as low as $35 delivered to the FFL with Lite receivers selling for $100. The 22/45 Mark IV complete pistol can be had for $300, so a complete Lite can be purchased for $400.
For rifles, the 10/22 is the right answer. Tactical Solutions are light enough for kids but are expensive new. Look for used models, Ruger and otherwise, at https://www.rimfirecentral.com/forum...y&categoryid=4