There is an online way to learn whether a particular Target store has a set in its inventory. But this method does not let you know the price or whether the item is on clearance.
FIRST, you need to get the set's DPCI number. Just go to Target.com and open up the page that has the set you are interested in. Scroll down to where the details about the set are provided. Under the heading "Online Info," you should see something called Store Item Number (DPCI). Copy this number.
SECOND, open the following website:
http://sd.site88.net/t.html" onclick="window.open(this.href);return false;
This is a very simple, uncomplicated site. Paste the DPCI number in the appropriate box. Then type in the zip code for the area where you are shopping.
THIRD, hit submit. That's it. You should get a list of your local Targets and whether or not the item is available. I have interpreted the term "Limited Availability" to mean that the store's inventory is unreliable and you are on your own .... they may or may not have one.
I have not used this much and cannot vouch for its accuracy. But folks at FatWallet.com use it all the time and seem very happy with it. Hope it is useful to anyone who didn't know about it.