That is about 25 dollars worth of schwinn. 75 seems a bit steep.
Before riding or testing this bike lower the stem. It's about 2" above the minimum insertion line.
The decals make it late seventies to early eighties.
The other posters pretty much have it nailed for the consumables, washing, waxing, & greasing.
I happen to use and like suicide/turkey levers though.
The only other hotrod trick I have for lower end schwinns is using a shimano uniglide or hyperglide freewheel. I don't know if you'll be getting into it that far though.