I'd say that if you want the best made; lowest costing headphones that have been in production for over 20 years try Koss Porta Pros. Get the older model that looks like it's from the 80's. It works great without an amp; folds up for travel; stands up to abuse; and generally is a great value. They can be had for $40.
I always hate it when people comment saying if you're able to stretch your budget you could get X, but...
These are so good I'm going to post them anyway. The Massdrop x Sennheiser HD 58X. I've had these for years and they're seriously phenomenal. They are open-back so if you're usually in noisy environments they won't be good, but the sound quality is amazing.