The price is already sky high for AKs. If you can get one at a good price id say buy the rifle first. Mags will still be available if the ban happens though prices will be higher but less than the inflated price of rifles.
Coming from the days of $75 romi kits, I have a hard time with the price of AKs these days. My 2 cents-build an AR.
GL either way, both are a blast to shoot.
You can build for cheaper. Customize as you see fit, build over time as to not drop all your cash at once, learn how your rifle operates, etc...
An ak build is just as fun. Akbuilder can get you started.
Keep an eye on craigslist, armsbroker and follow all local & federal laws.
If you have patience and some skill building an ak is an awesome project. You learn about every component as well as bragging rights. I have built two Romanian g parts kits from copes dist. And recommend the project to any real gun enthusiast. If your are a machinist (like myself) it really helps because they is some tooling for assembly that makes life easier. Good luck
I'm studying to become a gunsmith however don't have any real experience with machining.
To build an ak you really don't need to be a machinist. It just saves you some money when it comes to some fixtures you would need. You can just buy them tho and a headspace gage and all you would need is a press to get it together. Also an oxy-fuel torch to heat treat your receiver. After the first one it only takes a few days to complete depending on what stage you get your receiver.