First off, let's take the example of the Black Pearl, IIRC the Target DPCI for it is 204-00-0522. Are you familiar with
the CAG official Target clearance thread? It mainly covers videogame and electronics clearance, but it is also invaluable to researching and planning for anything at Target clearance or otherwise.
There is a link in that thread's first post to
the Target DPCI inventory checker (if you are unfamiliar with this tool, you will note the DPCI at the end of the link; simply change this value to the DPCI item you are interested in...that link above is already set to 204-00-0522 for the Black Pearl...then hit return/enter, then enter your zip code or city/state and then hit go). This inventory checker is critical to figuring out which Target stores around you might have a particular clearance item in stock, and in situations like this, which stores *might* have clearanced them out yet still have it in the system at a healthy discount, versus which ones still have it in stock, most likely at full price.
Now, when the list of stores around you is returned, the only values should be "Available", "Limited Availability", "Out of Stock", or "Not Available". "Available" means there are more than 2 quantity of the item showing up as in stock in the system at that particular location (either in the stockroom or on the shelves - you can then use the price checkers in the stores themselves to tell you the locations of the inventory) . "Limited Availability" means there are 2 or less at the location (and usually you will be shit out of luck finding them), "Out of Stock" means that it's still in the system at that particular store but sold out at that location (which, with clearance items, usually means it was clearanced so it is worth it to call those stores and get a price check on that DPCI), and "Not Available" usually means it is out of the system at that store or never was in the system/never was available at that particular location, thus if you enter that DPCI in the price checker in that store it should return "Item Not Found".
Note that clearance items will eventually drop out of the system and return "Item Not Found", at that point your chances of a return/rebuy at that particular store are nil since Target policy is to take back the item and salvage it - it's HIGHLY unlikely the CSR will go about looking up the last known price on it and reselling it to you at that price. Though, if you happen to find such an item on the store shelf at that location, you *might* be able to get the employees to look up the last price (usually the best clearance discount in the cycle) and possibly give it to you at that price. Also, please note that the online inventory checker is not always accurate - there is no guarantee of its accuracy but generally it is correct.
Since you're only looking for one item, I would simply call around to all of the stores listed/located near you (you can click on the store names and get the contact numbers, locations etc.), hit 0 to get the operator and ask for guest services. When they pick up, politely tell them you have the DPCI number for an item you are looking for, and would like to get the price on it. They will almost always do this for you. If they subsequently tell you the item is sold out/unavailable, ask them to tell you what the price is/was on it. "Can you tell me how much it was?" Call around to all of the locations, at the very least any locations that do not list it as "Not Available" - meaning call all locations that have it as "Available, "Limited Availability", and "Out of Stock". Note the location(s) with the cheapest price (and quantities in stock, if applicable). Hopefully you will have one or more nearby with the lowest price, even better if it's still in stock there. I would only give the employee the DPCI number, not the name of the product. The less information you provide, the better. You obviously wouldn't want to tip someone off if their store is sitting on a clearance goldmine.
Then, assuming you can't find a location that has it both in stock and at the lowest clearance price (which would obviously be the preferred method of obtaining it as it would obviously not require a return/rebuy), simply go and buy it at full price at the location that has it in stock, preferably with any form of payment other than the one you would like to use for the final rebuy. I.e. if you want to ultimately purchase it on your Target Redcard for additional 5% savings, initially pay for it with cash or another credit card. This way it actually looks like you are merely attempting a good old change of payment, although sometimes I am so blatant in my arbitrage I just initially buy stuff with the redcard then rebuy it with same, but I digress.
Once purchased at full price, take the Lego set and the receipt to the location that has it on clearance.
IMPORTANT: LEAVE IT IN THE CAR AND GO INTO THE STORE, FIND A PRICE CHECKER IN THE STORE AND VERIFY THE PRICE IN STORE FIRST, then once confirmed in store to be the expected lowest price or lower, go back out and get the Lego set and receipt, take them to customer service, and politely request to put it on a different card/change payment type.
They might need coaching/coaxing/cajoling here on how to do it if they have no clue or try to tell you something like "you have to do that within 24 hours of purchase/at the same store you bought it" - in this case you should suggest "is it possible to return it then rebuy it?" or "can I return it on that card/for cash, then rebuy it and pay for it with X?" If they tell you no, thank them grab the item and receipt and move on to another location or another attempt at this same location at a different time/day. If they return it, then subsequently discover it's on clearance at a lower price in the store and attempt to deny you in any way from repurchasing it, tell them you want to cancel/void/nullify the return transaction which they can and must do. Then, again, you can attempt it again at another location or at a later time at that location.
I've very rarely been denied, perhaps only a handful of times, 2-3% of the time at most. Usually the CSR is clueless/ignorant/indifferent and just chalks it up to the "item being on sale now" or recognizes it's on clearance and doesn't care or it's too late, as they've re-scanned it and I have my redcard ready and already swiped, transaction completed thank you have a nice day.
There are a rare few CSRs that know the actual store policy (no price adjustements on clearance, no return/rebuys on clearance), usualy these have appeared to me to be people who will be happy to return the item but refuse to resell it to you - instead they will hold it for themselves or their cohorts to get the clearance discount. If I encounter this, I simply have them undo the return transaction and deny them, after all there are dozens of locations all over LA County to give it a shot.