anything, and everything.
te hardest part of sewing, imo, is the cutting of the patterns in the first place. if you can cut clothes, then sewing them is relatively a doddle. though i do find attaching sleeves to shoulders a bit tricky, akward, annoying.
try making curtains. only straight lines there.
an apron
depends on what you want to do really. the only limit is your imagination. if its a decent make, then it should last you at least twenty odd years. so recouping your outlay shouldnt be a problem