The Custom 3 is a great option. Although they are now discontuned and have a terrible cord, they fit just under the $150 mark, are incredibly well balanced and extended in frequency response. The sound stage is well sized and linear in sense. It portrays good size to recordings.
The RE252 is another good choice, although, I'm not sure how easy it can be had for under $150. It's $199 new, but a used product might be found for within the $150 limit. I would consider its size to be similar to the custom, perhaps less linear, slightly less forward. It's more transparent, cleaner and more spaced in presence, and has more impact in note.
One versus the other, they're comparable products but geared for different tastes. The RE252 has a better cord and overall build quality. The "gummy bear" type casing is flexible but fit will vary from person to person.
If we're talking $200 retail and used, we also have more options in what to buy. One I would happily suggest is Etymotic's ER4, the S or P depending on amping, even the B if you want stronger highs. The main gripe is the bass frequency response does roll off a little early. Midbass and high bass is very good, but the deep notes just aren't there. The balance and sound stage is awesome though, very linear, well sized. These have been reference products for the last 15 years for a reason. Used, you can find them within your price range, and as long as you don't need deep bass, they're an excellent fit.
I haven't personally used a whole lot more in the affordable price range that gives a big, spacious sound. I think the only other thing I've used was the V-moda Vibe, but that has horrible locational cues, left, right, and that's about it. Even center isn't great, but damn if they're not fun to listen to.
I would kind of toss in the Denon C751 as an option. They aren't super spacious though in stage size, however their locational cues are excellent. They have great transparency and articulation of note. The sound is natural and very life like. To me, they are sort of a poor man's IE8, kind of a similar sense but a little less refined in response. The sound stage simply isn't big. It's more intimate, but separation and spacing is excellent. Still for the $105 they sell for, they have outstanding sound quality. Tip choice plays a roll in how they sound too. The stock mini single flange tip it comes with stock isn't quite right for it. For example, there's particular midbass and treble peaks that just go away if you switch to a bi-flange tip. Sensitivity is excellent and they have little need for amping. It's an earphone that certainly doesn't get enough praise or mention around here. Would I try and shoot for something better? Eh, that's debatable. It always comes down to the sound characteristics you're shooting for. It should at least be on the list though.