Anyone know of where I can get whistles in a lower key; like F,G, and A, that are low in cost? I wish Generation would make lower than Bb, is there any other brands like that that make lower keys? Thanks. 
It’s hard not to recommend Susatos for this. You can get a medium M-bore head and 3 whistle bodies in A/G/F for less than the cost of most single low whistles. And they’re really very nice whistles, IMO. I’ve pretty much relied on inexpensive Susatos for the odd keys in my inventory, with good results.
Thanks for that MT, I actually like Susatos. I will definitely look into that.
You can turn a Gen Bb into an almost in-tune Gen A just by sliding the head back (see previous threads)…
You could always make your own. The Guido Gonzato instructions look really good, and pretty simple.
You might check out the Jubilee Music Instrument Co. Daniel makes a ton of whistles in lots of keys. I recently bought two tenor whistles from him and they’re very nice instruments.
Peace
You might also check out Mack Hoover and Jim Becker’s whistles.
Mack makes a well-respected whistle - quieter sound is his signature.
Although Jim’s site doesn’t mention them, I believe other discussion on the board indicated that Jim might make lower whistles also. His are on the Guido Gonzato design.
Since I was cited twice, I’ll take the liberty to add that I also sell whistles… my Altos in B, Bb, A, and G cost 25 Euro. May I say only 25 Euro …? 
Yes, Guido, sorry to have left you out. Very nice PVC whistles at very reasonable prices. 