You can always take the front derailleur off, especially if you're not using "brifters". Set the gearing to what you wish, and remove the FD. You can get chainring chain guards that will sandwich the chain between two guards, and make it hard for it to fall off.
This is a pretty wide open subject as far as what is a "good" bike.
15 lb lightweight?
Classic Steel?
Townie
etc.
What is the intended use, and daily/trip miles?
One option would be to track down a classic English 3-speed, either restored, or needing to be restored. They often start at about $20.
The "Fixies" and "Single Speed" bikes have a growing popularity, especially in flat places, or some of them could support a 3 speed or greater internally geared hub.