We must have been posting at the same time. Your Murray is in pretty good original condition. I'd personally value it around $100. Someone has almost the identical Murray on ebay right now for $165. Not sure how long it's been listed or whether they'll get that much for it. Some sellers think just because a trike is older it automatically is worth a small fortune, ditto for some old bicycle sellers.
The Happy Rider is cheaply made and comes from Asia. It's missing the back seat upholstery which is common. The vinyl used is thin and tears easily, so the vinyl straps that hold it on usually tear loose and the seat gets tossed. The bolted head connection makes for a weaker frame design. I bought one years ago for about $25 and sold it for about the same price. These came out in the 1980s and I remember seeing them in toy stores back then selling for less than $20.
Out of the two, the Murray is definitely worth more.
Dave