All about seats

I am looking for first hand accounts of what might make a good sitting mat/cushion. I've been using regular bed pillows but the fabric in them has given way, offering little support aside from lumps of stuff. I looked around online, and the cushions sold are rather expensive, so I'd like some advice/input from people who have used specific cushions/equipment before I go and buy a glorified 80$ beanbag chair. Is there any one in particular that is worth the steep price tag associated with these products? What should I look for in particular? Is there anything I should look to avoid? I realize this is only tangential to the practice, but I couldn't think of anywhere else to ask such a specific question. Thank you.