Bye

I don't know how they write it in spanish, but everyone says "bye" a lot! 

1.  I am walking down the crooked, cobblestone street, and some young girls walking on the sidewalk with their mother see that I am an extranjero and they call out to me, "bye!" 
      - That seems kind of normal for me.  I try to speak the language of extranjeros that I meet.
2.  I tell my "mother" Sonia, that I will not be eating supper en casa tonight.  She smiles, gives me a kiss on the cheek, and says, "bye mamita".  (Okay, thanks for letting me know?)
3.  Sonia serves me dinner; I thank her.  "Bye" (Your welcome?)
4.  Carlos doesn't have enough money to buy eggs; Sonia becomes determined to find some dinero en efective (cash).  "Bye". 
5.  I get a grammatical concept in one of my classes.  "Bye".  Good, and moving on to the next grammatical concept. 
6. I am leaving the house.  Usually, it is adios o hasta luego, but I have heard "bye" a few times as well...especially when saying good-bye on the phone.
7.  We are at the market.  We settle on the price for a pinapple.  "Bye".

Generally, I think that it is a "word of conclusion".  "Ok".  "Situation resolved".  "Next, please.", but when learning a language, figuring out the nuances of where these words fit, seems slightly challenging. 

So far, I haven't aquired "bye" skills, but it would be lovely if I did in the next six weeks!