Upgrade compnents to fix "Everest" brand BSO/MTB so after a month of research,i've come to a conclusion that this might be an everest brand mountain bike.its a unified rear triangle and its frame is made out of steel.since i'm not gonna just let this bike stay one side collecting dust,with a budget of about maybe a 100 bucks,what could i possibly upgrade to make it a good ride? please just give me tips,any will do.and don't tell me that i should just trade for another frame
From some quick searching, it seems that "Everest" is a department store brand. Most upgrades that you would really notice would probably cost a significant portion of the value of the bike. Other than making sure it's in good mechanical condition, I wouldn't recommend putting much money into this bike.  Make sure the chain is oiled and there is the correct air pressure in the tires.  Make sure the gears and brakes are adjusted properly and work well.  Even something simple like a set of tires or new brake mechanisms could easily cost $50+.  Just ride it and have fun with it. Save up your money for a better bike.