First of all, welcome to the forums! It's so awesome to see new people flocking in this time of year!
Now regarding some of your questions...I did notice Eiyuutchi got to the topic first, but I'll put my views down anyway for the heck of it.
I was wondering what is a good one to get?
Also how much would it cost and where can I get it online (or stores that are in NY State).
Ebay has numerous decent sellers who sell all tamas, be it the super old school ones back in 96-97, to the ones around today! It's really up to you what kind you want. It all depends on your abilties to multitask, how much spare time you have, what you're looking for, and whether you wanna start off easy or not.
From my personal view, I suggest when getting back into the tamas, go with the V1 tamagotchi connections. Now they are pricey these days on ebay, but you can find them at semi decent prices on there if you look. I know chickeneater has a lot of V1 and V2's that are around 20-30 dollars depending on your currency. In your case from the NY reference, it'll be around 25 dollars plus shipping. V3's, V4's and v4.5's will obviously be found a bit cheaper online, but do provide more to the pet like schooling and point systems for the V4/v4.5 series. If you want to go for a newer one
If you want more of a challenge, but nothing to make you go all stressed out or frustrated, I think the older tamagotchis are the way to go if you haven't used them in a while. Or go with a japanese tama like an Angelgotchi or Mothra or Morino tamagotchi. The prices vary but you could easily get any of those for between 15-45 dollars depending on colour, rarity and shipping. Jason's Store on ebay is great for prices regarding those, and other olderschool virtual pets. There's also other japanese tamas made by bandai which all vary in prices you could consider like entamas (like V4's) uratamas (like V4.5's) Keitai akai and many others.
Since you wanna connect with your friend through, the Tamagotchi connections (versions 1-4 & 4.5) are the way to go...that and osutchi and mesutchi from 1997. This site actually has information regarding them on here.
Anyway there's so many to choose from! Rest is up to you how you wanna go about this.
Also those new Music ones, are they out yet? Can they connect to other people's?
This will be a shorter answer than the first. We have a topic regarding that on here I think it is in Tamagotchi News. Check out the topic there for more information on that tama. It looks like it's going to be cool!