I have yet to find an offbrand glock mag that I didn't hate. You really have to be careful this is a major cause in feed issues and when it comes to your safety or the safety of others you cannot rely on these. I might suggest buying a few and using them JUST ON THE RANGE until you feel like they are having no issues whatsoever.
Try TDSUS (Tactical Defense Solutions). They usually have the Glock mags for $25.
I've sen the Korean made ones, and they are $19.95 locally. I would stick with Glock OEM...always have. Try asking for used trade ins at your local gun shop...$15-20 here usually.