O_O I'm shocked,I think yall need to stick to fish lol.
Coasting in neutral in a 5 speed is fine,you do it everytime you stop by pushing the clutch pedal down.
Coasting in neutral in a auto is a whole different story, it can damage the trans in the long run as you are really only supposed to change gears at a dead stop, neutral is more an emergency thing on autos.
As far as saving gas nope, no more than just taking your foot off the gas in a automatic.
now with a 5 speed it does save gas only if you are stoping and only if your like me and you "engine brake" as your motor will dump alot of excess fuel trying to adjust to the gear. Not noticeable on an unmodified car, although it happens still, but with a car like mine heavily modded with a timing advance,no cat,no emissions,and running on 93 octane or better only. you will notice that excess in the form of fireballs out the tail pipe