The Stack Exchange is found in Treasure Island City, Silver Building, Apartment 10 B. The Silver Building is just up the hill from the TP and the Trade Center. 

In the Exchange section of the apartment, just past the shopkeepers, you will find, near one wall, items that are available at TT prices in person to person trading with me IF at least 50% of payment is issued in Needed Stackables. On the opposite side of the apartment, under the "Needed Stackables" sign you can find samples of the stackables that are currently needed.  The purpose of this service is to help out my crafting friends while also giving the general community a chance to find some good discounts.

If you wish to purchase an item in the Stack Exchange, and do not have enough Needed Stackables on hand to pay 50% of TT value of the item you wish to purchase, you may buy the item in question with only peds and pecs at TT + 50% of current MV in person to person trading with me.

Items inside of the Shopkeepers, in the front hall, are not a part of the Stack Exchange. However, the Shop Keepers are probably holding some good discount deals that you might want to check out while you are there browsing items that available for Stack Exchanges.(Some items in shopkeepers will be listed as shop items in this entry - I plan on keeping a full set of Rascal (M, L) armor in stock at all times in at least one shopkeeper.  When various parts of the set get sold, the replacement parts will be restocked nightly.)

A list of items available in the Stack Exchange can be found on Entropiaforum here:
www.entropiaforum.com/forums/shops/148284-stack-exchange-treasure-island-city-silver-10-b.html#post1841428

If you like the type of items you see in the Shopkeepers, you might also check out Omegaton Delta Tower, Booth #3 :www.entropiaforum.com/forums/shops/150514-killer-gear-killer-prices-omegaton-delta-tower-booth-3-a.html#post1875165  That's another estate I own. 

Availabilty:
I'm typically online most weeknights sometime between the hours of 8:00 PM - 10:00 PM, Central Standard Time (GMT -6). When online, my avatar, Maria mastermesh Mesh, can typically be found in the Stack Exchange - Treasure Island City, Silver Building, Aparment 10 B, or down the hill from the apartment, in the TI City Trade Center, just next to the Treasure Island City TP.  I'm occassionally elsewhere, such as at Cape Corinth, which is where most NBK hang out.  

If I'm not online, you may contact me via a PM to mastermesh on entropiaforum.