Tang/Receiver sight for a 39a mountie

[Brian Williams]

I have a 1894C and a 39a mountie and I have a Marble's tang sight on the 1894c and I would like to get a peep sight for he 39a..What do you folks like and where is the cheapest buys.

Or who has a Williams fp real cheap, which is what I am leaning towards.

 

[30Cal]

I've got the Williams peep sight on mine. This one in particular:
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=187449

I love it!
Ty