I usually go for the combo headphones + clip-on microphone.
I now have the Sennheiser HD280 pro. Not because I'm a DJ but because the foldability made traveling with them easier.
In your pricerange (even cheaper) I would recommend the Sennheiser HD201.
I had them as a student, and despite the cheap looks, they sound awesome and are very durable (my brother inherited them, and still uses them). It costs around €20, which leaves ample budget space for a decent clip-on. I usually clipped it to the headphone wire, because I always forgot to take it off when I got up (but never forget to take off my headphones).