Not sure why you would want to on a sub $200 bike unless the old one is broken. A change of elastomers in the fork might rejuvenate it if it is soggy. Since a new equivalent bike is $130-200, just get a new bike. Cost about the same as fork and new tires. Other sources would be local thrift shops, garage sales, the bike rack at any large university at the end of the school year, police auctions. Walmart also sells forks and tires, just remove the frame and handlebars and you have a nice new fork.
Ditto tires, just remove the rest of the wheel and tire + tube is right there.
Steve