I don't think these cans are as hard to drive as some folks on this forum maintain. I have new K702s. Curious to hear if I'd get any sound at all, I recently tried listening with them to music on an older Dell laptop with no card, just an onboard A-D chip. Sounded fine, though I'd surely notice a difference if I had a high-end amp. You may have a headphone jack in your receiver. These usually aren't high-end, but you'll get decent sound.
My current interim desktop headphone amp is a Presonus hp4, which is a cheap and handy device to have since it has 4 phone channels. They often sell used on Ebay for under $50. This or something in the same low price category could tide you over till you can afford something more ambitious. In your income category I would suggest exploring the Do-It-Yourself options if you can learn how to solder and read circuit diagrams, since the price-performance ratio is generally better than pre-built. Or buy somebody's used DIY amp here in the For Sale forum.
