You foster the interest, and show him/her the joys of shooting and the interest should last. The problem will be that they outgrow a youth gun and the price goes up. Bought my son a youth 20. Hurt me to shoot it. When he started wanting to shoot mine it was time for his own full size. Rossi has this one. budsgunshop.com/product_info.php/products_id/27886/rossi+usa+20ga+youth+22+modified

I would look for a USED Remington 1100 or 11-87 20 ga with rem chokes if you the stock shorter buy a 2nd stock to have cut down and when he grows you will have the original stock to reinstall

Jay, I'd go with regular size shotgun. Youth guns don't always have the weight or balance for a good youth experience. Buy whatever shotgun you can get your hands on in these challenging times. Here are couple for under $500---------budsgunshop.com/product_info.php/products_id/111345/winchesterchester+sxp+waterfowl+max-5+20+gauge />----------budsgunshop.com/product_info.php/products_id/97602/cz-usa+cz720+g2+20+ga+26%22+mc3 />----------These are in stock

Jay, you are going to want something that is versatile. This is a full featured Youth shotgun that has screw in choke capability, tube capacity for the type of shooting at hand from target to hunting. All the features in an adult sized shotgun in a Youth sized package that he can grow into : vanceoutdoors.com/products2.cfm/ID/34532