I have some 7.62 x 39 30 round steel and Arsenal Circle 10 mags that I'm looking for magazine couplers. Can anyone recommend a DIY or brand/model and vendors that's not crazy expensive?

Also, I have 4 Croatian mags with loose floor plates. The magazine functions fine, but I don't like the loose floor plate. I was unable to tighten them. Is there an inexpensive brand/model and vendor that you can recommend?

Thanks

Apex is always a good place for small parts like base plates. Not exactly cheap, but unless you find a bin of them at a show, you're probably going to pay about this much for them anywhere online:

AK Magazine Floor Plate, *NOS* - $3.50

If you can find some other parts you need, it would help offset the shipping.