IMHO, don't be cheap and don't buy the cheapest you can. Quality mags may cost more, but are well worth the added expense.
I purchased some surplus mags once. By the time I got through the garbage mags, the only good one left cost me the same price as buying 1 good quality mag to start with.
(I think I know what I said, but the bottom line is "BUY QUALITY MAGS")
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)