Replacing a toilet seat is an easy repair. Most hardware stores will carry an inexpensive basic seat, and possibly, a better-grade one. Look to home centers, design Web sites, or bath specialty outlets for a greater selection.
Almost all modern replacements mount in the same fashion, but some antique reproduction models, do not feature the plastic cap covering the plastic bolt. These reproductions have threaded studs integral to their design. Simply push the studs through the holes in the bowl and tighten the nuts. Always make sure the replacement seat has the same contour as the bowl.
About half an hour
Screwdriver, slip-joint pliers, hacksaw if needed
Removing and replacing plastic bolts
Replacement toilet seat, penetrating oil