Hi!
I am a freshman in college desperate to start on piccolo. I really wanted to play a piccolo for years but never had a chance until now. I asked my instructor and she mentioned about Yamaha and Roy Seaman. I heard Roy Seaman(Zentner) ones play good but not too many good stories about Yamaha. I rather heard Yamaha piccolos are hard to play in tune. All she said is that I need to get the one made out of grenadilla wood which can vary very much by brands and her not specific suggestion is greatly confusing me.

Do you have any recommendations on piccolos I should consider? Also which site do you recommend for used instruments? I looked at usedflutes.com which has a lot of ads- however I want to try out before I make the purchase.

Jupiter has come out with a grenadilla picc that is very good, if you are interested I can get more info for you

I have a Yamaha YPC-62 and I have been very happy with it. I have found that the cut of the YPC-62 embouchure cut allows the player a lot of flexibility with intonation. From my point of view, it's not that the YPC-62 plays out of tune, but the flexibility requires the player to have a good ear. I personally think that's a good thing. No piccolo or flute will play perfectly in tune on every note. They all require the player to listen and adjust as needed. That's what separates a Pro from a wanna-be...

I found that local repairmen they always buy-in used flute or piccolo, and then they repair them and adjust them, and sell them at half price. Early this year I bought a Yamaha YPC-82 from our repairman.

http://i927.photobucket.com/albums/ad112/pyrioni15/DSC01982.jpg

Handmade, silver headjoint, granedila wood body, undercut tone hole. Only the price of a YPC-62. Adjusted by the repairman, played perfectly.

After I am bored with it, I can always sell to other guy at same price, or even higher to American bidders(because in US and many rich countries the prices are sometimes doubled).

It is always a great idea to buy from a repairman instead of players, because repairmen have reputation to keep! And they made only 10% profit, to me it is like only a repairman cost.

I mean only 10% margin just like a cost of repair fee.

I never played piccolo before, this was my very first time played this YPC-82 during a concert where the conductor forced to play, 9 months ago:
http://www.youtube.com/watch?v=_T5kJ8KGHoc

I suck, sorry, just to give you an idea how it sound. I am not a piccolo guy.

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There is another reason why beginner piccoloist shouldn't buy from players or online, because unlike flute, if there is any hidden leak on your piccolo, it could be a living hell for you for a very long time, and many repairman doesn't like to repair on piccolo, even if they do, they will charge you very very high repair fee !!! So, you are a beginner, buy a new piccolo from a trusted music store or buy used from your local repairman that is what I did!!

I don't understand why your instructor has so much to against Yamaha? When I played in Vienna last year, conducted by Peter Gruf - (Vienna Philharmonic Orchestra's concertmaster & conductor), there was a piccoloist, she only used the most basic Yamaha model YPC-32 - plated headjoint, plastic body, only costed her US$490, and she played it very nicely the Vienna Strauss musics:

http://www.youtube.com/watch?v=7Zg0Bq2VV3A

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Not saying other brands are bad, but I have seen and heard many many piccoloists are using YPC-32 in many student or youth orchestras or bands.

I have an older Zentner and it is fantastic.
I have a friend who played a Yamaha 62 through her masters degree in flute performance at a very prestigious undergrad and grad university. (Worldwide recognition in their music programs.)
Her Yam 62 was stolen and she replaced it with a custom Weissman, which had better tone possibilities but is, without a LOT of practice, very hard for her to control, pitch wise. This woman, BTW, has an incredible ear for pitch. The Yamaha was simply much easier for her to control. She likes to play my Zentner, because it has (for her) both a lovely, rich tone and an ease in controlling pitch.

The newer Roy Seaman piccs are made by Gemeinhardt, and they are simply not as good as they used to be, in my opinion.
Now, our symphony principal who doesn't play picc a lot has an older Gemeinhardt 4W, and it is an outstanding instrument. The Symphony piccolo chair has a handmade Burkart, which is an absolute dream to play, but cost 4 or 5 times what the Gemeinhardt 4W would.

So...if you have the money, I would try a Burkart. If you're on more of a budget, I'd go for a used Zentner or (older) Seaman-I bought mine for $1500 a few years ago.
But a refurbished (by a VERY GOOD piccolo tech!!) Yamaha 62 or Gemeinhardt 4W will do very nicely, if that's what is in your budget.

Oh, and DO try out before you buy. Also have a very good tech look over the instrument. Ask your flute prof who takes care of his personal instruments.