The best place to restock depends on your connection, and the amount of time you wnt to spend. the bakery is good for fast connections to make big profits, and slow connections to make very small profits. the same goes for the food shop, stamp shop, coin shop, book shops, and a lot of others.
personally, i like the card shop since fair profits can be made and the rarity of the item can be deduced by the colour of the card.
any shop is good for restocking, if you have a keen eye.
this topic here helped as well:
http://www.pinkpt.com/forum/viewtopic.php?t=26020
Losers are those who do not try