The puzzle seems to expect a COIN as the answer. But, theoretically, it could be ANYTHING that has a head and tail AND he already knows to be there in his bag. (e.g. a toy / stuffed animal or bird, or even some live creature – may be a snake – he had taken with him for whatsoever purpose.)

The maid: ‘Put the note inside the book between page 1 and 2′.

Er… but in a normal book, pages 1 and 2 are on either side of the same sheet. Then how could it be possible that the note was placed ‘between’…? So, she must have lied, right…?

Ah… well, but then, the next sentence (in the puzzle) says they looked ‘between page number 1 and 2 but it isn’t there’. Well, if pages 1 & 2 were indeed on either side of a single sheet, how could they “look between” the pages? It’s possible only if pages 1 & 2 were on separate sheets.

Now, The mail guy: ‘Moved it to between page number 2 and 3’.

Well, in an ordinary book, it’s very much possible. But… check the scenario above once again…  It says they ‘looked ‘between page number 1 and 2′ which is possible only if those pages were on separate sheets. If that was the case, the pages 2 & 3 must be on either side of the same sheet.  In that case, Mr. Mail man should be the one…

(Aah… wait…! What if the book was even more ‘strange’ and numbered pages on one side of paper only…? Then both the cases (‘between pages 1 & 2 and between 2 & 3) would be equally possible. Can’t be ruled out, especially when they could ‘look between’ pages  & 2…!)

A single grasshopper multiplies to 15 in an hour…?? 😮 What kind of a ‘super-natural’ ‘hopper it is…?!!

The expected answer seems to be the ‘name tag’ thing as mentioned in the first answer, but that’s a bit extra-ordinary. How often would you find a policeman and  fireman, both on duty (wearing uniforms that include name tags) sitting idle in a house, watching TV? Put the other way, how natural is it for a policeman / fireman to wear name tags when not in uniforms (off – duty)?

Go for the third one (AND hope that power supply doesn’t resume anytime soon…!)

Saw dust…! Entirely made of wood, yet a saw won’t saw it. 🙂

Hi Mr. 

Nice to meet you…! 🙂

A coffin seems to fit the requirements… still, it may not be the case  always.

“Who makes it, has no need of it” — No, he may also need it someday, though the one used for him need not have been made by himself.
“Who buys it, has no use for it” — Even though pretty unlikely, one may buy a coffin to be used for himself when time comes…

Of course, the third clause fits perfectly…!

B[ONE] – [ONE] + [EAR] = BEAR