Its not discontinued, you just need to buy a cart and flash the rom onto it.

I always find myself composing either on my roland sh-201 or my acoustic upright piano. I was trained on the piano and have been playing forever, so I feel like thats the one instrument that I can truly doodle around on without really using my intellect and just "feeling" things out.

That said, I think theres certainly something to be said for composing outside of your comfort medium or instrument, as we all have compositional habits when it comes to using whatever instrument we've been trained on. (I for example i have a couple key signatures that i refuse to compose in if I'm using the piano be cause the fingering drives me nuts).

To that end, even though I  prefer piano as  an instrument or fast/milkytracker for sequencing, stepping out of my comfort zone and working with stuff that is really off the beaten path (i.e. nanoloop) can really be helpful for breaking out of a rut.

you should ask nonfinite for a bleep bloop cart if your looking for lsdj. personal i think its waaay better than nanoloop but im kinda biased.
anyway, if anyone cares i love writing melodies on the sk1 or lsdj, but a dingo loaded up with lgpt is my new favorite thing

What cartridges do people prefer to use with a gameboy? I'm thinking about getting into making chiptunes with a nanoloop or lsdj and I'm wondering what is most reccomended. I know the lsdj is discontinued but there are always some on e bay. Which one should I buy ?

guitar, usually my very simple Yamaha EG-112, and then copy out my most favourite of melodies from the day on one of my GB Cameras, and then just create something juicy either by using LSDJ or a varied collection of VSTs.

I personally like to hum a few bars on a kazoo....

My starting instrument depends on the project, and in fact, starting from different instruments is how I try to introduce variety in my work.

More often than not, I'm just using the qwerty keys of the tracker.  The samples may or may not be tuned correctly.

Other times, I've used a chinese 12-string guitar (mine has a pickup glued to the soundhole):

Or the easy sequencer+faux kaoss pad of DS-10:

Any real piano, as long as its not a cheapo or severely out of tune. at home now i only have this:

... While using plugins like this:

no that's a launchpad

this is a thing of beauty

and the same price as a used car

that is a thing of beauty

Some sort of keyboard and after sampling keyboard riffs/whatever:

..connected to Live.

nothing beats an electric piano
though the whole mobility of jamming on a gameboy is nice

As a bartender, I agree with with post.

i have a manservant follow me around with a special typewriter and transcribe every note that pops into my head