>>1642786perhaps i was a bit too harsh
yeh you can use it, it's still a bike and got working gears, but if you really want to get some joy of riding it around town then make it a little bit easier on you
start by ditching the horrible useless quill stem suspension fork and get a rigid one, Fib makes inexpensive ones and you can find them easily on Mercado Livre, but ask around at your local bike shops first if they have any rigid 26" fork
second, it probably got loose ball bearings bottom bracket, replace it with any sealed type bb, even cheap GTS ones will do
thirdly, get a lower stem, or better, a quill to a headset stem adapter and put a normal stem, it will make you sit on a normal riding position rather than a couch sitting position
and lastly and least important yet most expensive, replace those knobby tires for slick ones, Kenda Kwest is a good one. You can do all that for about R$300
it really sucks, you may feel like you got scammed but truth is that your average brasileiro don't know shit about bikes and most people really do think that if it is a Caloi it must be good, the seller probably think that bike is worth 300 reais. Really, that's the only reason Caloi is still around since they've lost their inovation and quality long ago.
Just don't forget, if ever shopping for a bike again,either go full gringo on modern bikes or look for pre 2000's national stuff.