A reasonably price for a Catwalk?

I think anything around $1,000 is a good price for one at this point. If you can find one for less, even better, and I personally wouldn't go over $1,200 now considering it's been on sale and shows up on Bluefly regularly, too.
 
There's one on ebay and if the pics are legit, then it's authentic (I have no affiliation to the seller/listing)

Saks had it for $697 when the huge sale hit, but it sold out ASAP.
Saks in Beverly Hills has the patent version at that price, in stock right now.

Otherwise, it's full price at YSL and not going on sale any time soon b/c they are carrying the nubuck version forward for next year

Bluefly has been sold out for ages.

Anyways I know all this b/c I was in a mad rush for one.
If you call an SA at Saks, they will be on the look out for any returns they get (which has actually happened once shoppers get buyer's remorse!)
 
Here is the link to the sold out one on Saks. San Diego Fashion Valley still has one left so if you have someone call the 877 Saks number and give them this style number 0413689957051, they should be able to confirm and price match.

http://www.saksfifthavenue.com/main/ProductDetail.jsp?PRODUCT%3C%3Eprd_id=845524446169060&Goto=product&site_refer=360iSSPPLP&kw_refer=Yves%2BSaint%2BLaurent%2BCatwalk%2BNubuck%2BBag&sisearchengine=55&siproduct=Yves%2BSaint%2BLaurent%2BCatwalk%2BNubuck%2BBag-PLP&clearppc=1