Might Get Some Plastic On A Few Of My Favorite Coins

If this is only for protection and storage, you buy some DIY slabs much cheaper.

I understand why some folks want their coins in plastic. Some people think that they are better preserved, and technically they are. Remember when you slab your coins, NGC might not slab them for one reason or another. They are seriously inconsistent with their grading and slabbing. They dont slab the ancient India, Chinese, Hunnic or Roman Republican cast bronzes. They tend to only slab mainstream coins with solid historical reference. They also dont slab the difficult to determine coins like those of the Black Sea that have been well faked in the late '90s. So, if you want to slab be prepared to spend 40 dollars a coin and then to be raped on the return shipping. Turnaround time is 1-2 months. I found them to be too commercial and neglect a wide variety of ancient and medieval coins.

Try Airtites with an insert. They rattle in normal airtites, but if you get an insert slightly smaller than what you have you can make an insert of the correct shape.

Please don't imprison them. The main thing that separates Ancients from more modern coins is the intense history that is stored in them, that history continues with you if you continue to handle them, interact with them and share them with others. In my personal opinion I don't think we own these coins, but we are merely caretakers from them, and keeping the history in them alive, but once they are slabbed in plastic they are no longer living historical objects, the became past relics. I understand that this is my own personal opinion and has no objective truthful basis, but you might consider this way of stewarding for your coins. I try to handle my coins almost everyday, and show as many people as I can, to keep their history alive.
Too many objects have a history of sitting in the houses of wealthy men, it's time for us to create a different history for these objects. Here's how I store my coins, unorganized, in a box. (Although I am building a classic style cabinet for them.) I apologize for the huge rant, I understand that it has no real basis in any fact and only my opinion. Whatever you do please enjoy your coins in the way that makes you happy. I hope that you consider my path.