Originally Posted by vintagebicycle

$50 was a steal for that bike, a few hours and some fresh lube and that'll be like new.
The Sport was a plain steel bike but it rode well. I've got one I turned into an upright bar cruiser for daily riding. Pretty much the same as yours in a men's frame with MTB bars and brake levers, plus a new set of alloy wheels.
Any ridable bike is worth far more than $50 just for transportation purposes. Ad some age and style and it's worth even more.
If that were mine and for sale, I'd have gone through it top to bottom, given it a good cleaning and polish and put a $325 price tag on it. As it sits I'd have to say around $125 to $150. Face it, you can't buy it new, there just isn't anything even close to that made new, at least not that's sold in the US these days, mixte frame or otherwise. Mixte frames also weren't made as just woman's models, they were billed more as a unisex type design. They are far more rigid than a ladies frame and far better looking. They are a bit rare these days as there simply never were a lot of them sold. I'd venture to guess about 40 to 1 mens to mixte frames? Maybe even a bigger gap than that. Not that rare in this case adds big money but if your after that style bike, it can be hard to come by.