[AllahLover69]

I'm looking for a portable amp to increase the sound quality of my ATH-M50xs along with my HTC One M8. I'd prefer the price be below $50, preferably lower, unless the increase in sound quality is that much better. I plan on bringing this on the road and to school, so I'd like it to fit in my pocket along with my phone easily.

 

[PETEREK]

You could get a used Fiio E11 for under your budget off Amazon. 
 
http://www.amazon.com/FiiO-E11-Portable-Headphone-Amplifier/dp/B0053KWDES

 

[PETEREK]

I use an E12 and when I use it on the go I use one of the rubber Fiio bands to hold them both together and then put half in my pocket and half out of my pocket like a clip. It works well. If you don't want something quite that big, you can get the Fiio E6, though it will just end up dangling off your 3.5mm jack on your phone, I never liked that about it when I had mine.

 

[Richsvt]

JDS Labs cMoyBB $59.99 assembled- cheaper if you build it yourself.
 
You can get others who have done something similar for less.
 
I have the JDS one and love the Bass Boost. They will also customize it somewhat depending on the phones you plan to use...I like it a lot considering what it is. Very decent sounding. Good Output.

 

[AllahLover69]

The E11 looks great. Ignoring my current budget (I can wait a little), would you recommend the E11 over the Andes 07k?

 

[PETEREK]

I've never used the 7K, so I can't comment on that.

 

[Kamakahah]

Fiio E11k for just above budget. Topping NX1 for just under. I'd probably say to go for the e11k for Fiio customer service and quality.

Alternatives:
Used C&C BH. Used Fiio E7k (amp/dac)
Both can be found occasionally for around $60 if your patient.

 

[RoMee]

The Topping NX1 is only about $45 and is getting some good reviews.
 
http://www.head-fi.org/t/696825/topping-nx1-portable-headphone-amplifier-impressions-thread

 

[AllahLover69]

Thanks for your guys' input. I think I'm going to be going with the E11. Should I buy for $60 New or $50 "Like New" off Amazon? Sorry for asking such a dumb question, but budget is of importance to me right now.

 

[Kamakahah]

AllahLover69
Make sure you are grabbing the newer E11K and not the original E11 unless that is what you want.

The "Like-New" is usually just fine. never had a single issue.
For the most part they are just open box items. Someone ordered to compare it for a few hours and sent it back.
The return policy at Amazon is excellent in case there is a problem, so you might as well save the $10.