Needless to say, my favorite one is Dollarama!
Different dollarama locations carry its very own set of gems. The ever changing inventory of goods depends on supplier's product offering. Thus you may see different selection of goods on every visit (which also depends on your frequency, of course). Due to the limited quantities to which they order, different locations may carry different set of goodies. In some stores you'll find the "kitchenware" aisle to be filled with "betty cooker" products, perfect for all your baking needs. Or in others, you'll find OPI nail polish colors in the "beauty/cosmetic" section.
This leads to my recent find, to which I have gotten addicted to using lately: Nail stickers!
To be honest, I only bought 1 on my first visit. Simply because I don't know how long they were selling it for. Sometimes the products have been sitting on the shelves for a long time. They lose their adhesiveness. To my pleasant surprise, they stick REALLY well on my nails! Best of all, they lasted me for 2+ weeks. For $2 per pack (potentially good to use for 3 sets), this is definitely a steal. I've also took some pictures of how it appears on your nails after its set.
My second find are the rubber hair elastics! These are perfect for if you want to tie up small batches for a fun hairstyle. The elastics are more durable than those with a glossy surface. However, a downside I find with the elastics is they don't come in 1 color. Additional bobby pins would be used to cover the elastics. Other than that, I have no complains!