The Pioneer SE-A1000 can hold its own against heady competition, such as AKG's K701/702 but at a much lower price point. However with a price of $46.97 on Amazon, I'd say it's literally impossible to find a better headphone for less money—true full-range, audiophile quality for under $50 is a rarity.
A number of other retailers are selling them for between $50 and $65, including Sears for $59. I originally noticed them at a Best Buy Magnolia on Clearance for $60, but I had them price-matched to Amazon.
how would this compare to sony MDR 7506 and audio technica ATH-M50? i got the M50 just two weeks ago.
Those are both closed-back, studio-oriented headphones. The SE-A1000 has a more expansive soundstage, and sounds airier, but bass rolls off a bit quicker. The huge earpads and open-back design make the SE-A1000 much more comfortable for long session listening, but they don't block any external noise. The SE-A1000 is a very different design vs. the two models you mention.
This is one of the most engaging headphone models I have ever listened to, but bass-lovers used to full-sized closed-back headphones might not like the way open-back designs sound in general. When compared to the highly popular AKG 701/702 series, the Pioneer compares very favorably at a fraction of the price.