If you need a stretch, then yes, there is a major difference in quality when it comes to price. The $20/yard performance lycra is that expensive for a reason, and for once it's not useless brand marketing or artificially inflated prices.
Finding the correct fabric for the purpose intended is part and parcel of the learning process of becoming a better sewer, but don't discount sewing method as well. Finishing off seams with a zig-zag (if you don't have a serger) is a good technique to get into the habit of using. But if the runs in the stretch fabric happen in the middle of the grain and not at the seam, then it's more likely the quality of the fabric than the methodology. Though, lemuries is right and it might also be equipment failure - a dull or burred needle can cause snags in any fabric, which in turn will unravel further/faster in a lower-quality fabric.
Founder and Vice-President, Madison Area Costuming Society, a chapter of the International Costumer's Guild
Strange Land Costuming - www.strangelandcostumes.com
Director, SF&F Masquerade
- COSTUMECON34 - Madison, Wisconsin - May 6-9, 2016 - www.costumecon34.com