The first two of these I bought in the blind bags were Fiona and Lumpy Space Princess. I don't mind getting the two female characters, but how about Finn and Jake? How about even just a BMO? All my son really wants is BMO. And then our third blind bag was a second LSP, so we decided to stop buying them in blind bags. The idea looks good on paper and I totally still want Finn, Jake and BMO, but buying them through blind bags for $5 each is not the way to go. I could spend another $15 easily just opening more LSP duplicates.
So hopefully should people decide to buy these in bulk or simply sell their duplicates on eBay then the second hand market will be the best place to get the characters that you want. They all have the same sort of shape, though Fiona has legs and LSP does not, but still it is difficult to feel around in the bag and think you're getting a particular character. It is the true essence of blind bags, which might be fine for people with popular YouTube channels but for me I'll just buy the ones I want on eBay if I should decide I want them.
7/21/15 Edit: We purchased another one at the request of my son and it turned out to be BMO, much to our delight. A few weeks later we found some at another Target with holes poked in them- as if someone was trying to reveal who was in what bag- and this allowed us to get both Finn and Jake. I asked my son if we could be done and not get Princess Bubblegum but he still wants to find her. Someone had also poked a hole in another one at Target to reveal the purple of LSP so I can only assume they were hunting for BMO. Maybe they were looking for Preebs. I don't know. My wife also informed me that these are $5.99 and I do believe I marked them as $4.99 in the original post.