Suggestions for a quality 16" bike for a 5-year-old boy who can already ride ramps? - cheap bmx ramps

Kid is 5 and has just had his 12 "Toys-R-Us bike. He loves to go along (3 +) miles and go over ramps home on foot. It was a hand-me-down 16" for a few weeks assembled, and we want to make your own 16 "on his birthday. We will want a bike that is lighter than the bikes make cheap Toystore when you start BMX racing in children. brands? models?
Thank you.