The EP-100 can be had for around $20 on eBay, Amazon, etc.
Comes with a small plastic carrying case and three pair of bi-flange tips, each in different sizes.
This IEM uses SPL2 technology, which is apparently supposed to keep volume levels safe, and reduce distortion amounts.
The packaging is pretty simple- a cardboard backing with a plastic front.
Comfort - I was immediately disappointed in the comfort of these. The tips were really causing a significant itch inside of my ears. Since I don't really have other IEMs with a 2mm nozzle like these, I had to resort to some DIY memory foam tips (thread of these can be found here http://www.head-fi.org/t/383917/how-to-best-custom-tips-for-iems-ever-imho-with-pics
These are a lot more comfortable than the stock tips for me.
Build - I was somewhat disappointed here too. I understand that these are only $20 or so, but these are truly the cheapest feeling IEMs I've ever used, other than a few $2 ones from Chinese manufacturers.
The housing feels like it is made out of pretty cheap plastic.
Cable is thin, plasticky, and feels very prone to memory effects.
Isolation - I'm impressed here. With the 2mm nozzle, these can be inserted fairly deeply, which gives some good isolation.
Sound - I expected a bit more from these, but at the same time, I didn't.
The signature itself is similar to many consumer-oriented IEMs- warm sounding, with plenty of bass. There is an obvious bass bloat without proper EQ. I also found these to be somewhat dark in the treble region. With some EQing, I got the sound to be quite good. I lowered the 20-80 Hz about 2 db, lowered 128-500 about 3.5 db, and increased 4k-16k Hz about 2 db. After this, I got a little more of an idea of what these IEMs can do. Sound is moderately detailed for what one would expect for $20. I'd say less detailed than something like the Sony MDREX10LP, or the Philips SHE3850 though.
Overall, I'd say these are 'okay' for $20. I would hesitate to recommend these to anyone, especially someone that listens to their music loud (I can get them up to listening levels, and no more, due to the SPL2 tech used), or because of the sub-par build. Isolation is definitely a big plus with these though. So, it would ultimately come down to the person's needs.