Well I got my electric tuner out, and have discovered that my whistle (Walton’s Mellow D) that D is too sharp. Even when I try to blow as gently as I can, it’s still sharp. So now I’m looking for a new one. What CHEAP ones do you guys recommend? I was thinking maybe a Clark’s Sweet Tone or it’s cheaper brother, Clark’s Meg. Now I know pocolargo already has a post simular to this, but I want some advice about the cheap ones, and the cheap ones only. Thnaks! 
I think the Sweetone D is a very nice whistle, especially at the price they are. Well worth the money. I bought one for a friend’s daughter, she’s well happy with it.
And they come in lots of nice colours. 
Have you tried moving the head of the whistle out a bit to flatten off the notes. If it is stuck, you may want to try the hot water trick to loosen the glue if it has. It will of course flatten all the notes a bit, but may solve your problem. I got my waltons second hand and it is a real favorite with no tuning issues at all. My other favorite is the Clark original but as always it is very subjective. One always needs to try the generations and feadogs and don’t forget Guido’s Low tech http://guido.gonzato.googlepages.com/whistle.html he may sell you one and if he does you won’t regret it. Mine is absolutely fantastic and is my car and couch whistle.
The Walton Mellow D is a very nice whistle IMO. The bell note is sharp, as you said but this whistle is too good just to lay aside. The thing to do is to extend the length of the tube to bring it into tune. Jerry Freeman does a great job with this on his Mellow Dog.
On my Walton Mellow Ds (I have about 6) I extend the legnth with some rolled copper sheet and epoxy glue. There are many people here that can sort this problem out for you.
I’ll have to try the hot water trick sometime, but this is also a good excuse to try out some of the different types of whistles! lol ;D
I love the sweetone. I have a handful of other brands and I keep coming back to it. Its my main whistle. However, I’ve bought three so far and they’ve all been sharp for the way I play so I pull out the mouthpiece a bit too til they’re in tune with my tuner. I tend to blow a bit harder and it works for me. I have one in my gear bag, one in my car and one in my practice area.
Lisdoonvarna
I love the sweetone. I have a handful of other brands and I keep coming back to it. Its my main whistle. However, I’ve bought three so far and they’ve all been sharp for the way I play so I pull out the mouthpiece a bit too til they’re in tune with my tuner. I tend to blow a bit harder and it works for me. I have one in my gear bag, one in my car and one in my practice area.
Lisdoonvarna
the bottom D being sharp is a known Walton’s Mellow D issue. Moving the head to bring it into tune will flatten the rest of the whistle. That’s why Jerry adds a bit of tube to the end when he tweaks these.
I have owned a bunch of cheapies, but I like Waltons best. However, if you want a good whistle but don’t want to lay out a bunch of cash, get a Dixon. The non-tunable polymer is about $24; the tunable polymer is about $35. The trad ($24) has received very good reviews, too.
Just use a bit of tape - I use electrical tape - to extend the tube a little. This will give you a chance to see if you want to do a more permanent fix. The tape is easy to adjust until you get it right.
A few wraps of aluminininium foil tap (the stuff you’re actually supposed to use for ducts) makes a nice pemanent fix after some experimenting.
Okay, you had plenty of advice from helpfull people about fixing your tuning problem by extending the bell a little.
You also asked about alternatives.
I have a Walton’s and agree that it has a nice tone - particularly the lower octave.
Another ‘cheapie’ I quite like is the Feadog. The mouthpiece feels a bit more ‘delicate’ than the Waltons and the tone is similar - nice and ‘round’, not squeaky like a bad recorder or hissy like a flute. The only issue I have with it is that it takes a bit of sensitivity to overblow it into the second octave and hit the note dead right every time.
The Clarke whistles are said to be the ‘original’ and I bought myself a ‘Meg’ to see what they were like. they have a reverse-conical bore and are made by rolling a sheet instead of out of tubing so you notice a seam down the back of them. I find this uncomfortable ad distracting. The sound of mine isn’t as round and full-bodied as either the Feadog or the Waltons, but it is pretty easy to control moving between the octaves. From my experience with other wind instruments I would guess that this might be due to the conical bore. The sound has a slight tendency towards squeakiness in the lower octave and hissing a bit in the higher octave.
The other cheapie whistle I know of is the generation - as sold in every music shop just about everywhere. I don’t kow if it is a sign of poor quality control or careless design, but every generation I have tried seems to have a sound which is both hissy and squeaky in the lower octave. Some of them seem to overblow into the higher octave quite nicely while others seem to be all hiss and squeak !
You can easily get all of these whistles nice and cheap on e-bay so why not try them all ?
You know, I’ve completely forgotten about ebay. Great place to get things cheap. I’m sure in the end I’ll have lots of whistles! lol I’ve also thought about, with the help of my dad, making my own whistle out of PVC. But is this something that maybe someone with more whistle experience should try to accomplish?
Definately worth giving it a shot. There are some really easy to follow guidlines around and the only way to get experience is to try it. PVC is a really cheap option and the results can be be excellent. It really helps in understanding whistle physics which is an added bonus to playing the whistle.
There are some really easy to follow guidlines around and the only way to get experience is to try it.
Sounds like a potentially fun project - are any of those guidelines available on-line, do you know ? If so, URLs much appreciated. 
I seem to recall that there are one or two professional whistle makers who use PVC waste pipe as their raw material. 
Kepla- That’s the same site I saw on making whisltes from PVC. The guys guy really took the time to make it very detailed, with trouble-shooting.
I also found this site, which shows you how to make one from copper.
http://www.geocities.com/SoHo/Lofts/6611/makewhis.htm
Wow - thanks guys ! That’s a couple of great links.
Looks like I need to get myself some lengths of pipe/tubing a try it out.
Our local hardware store have all sorts of stuff I might try - - -including some clear acrylic tube which might make a really cool transparent whistle !
PVC, copper, aluminium, steel, acrylic - I’ll have lots of fun trying.
Thanks.