Get the Isreali one. Best bang for the buck. Quick fulfillment.
How much juice do they need?
If you can get by with around 2A or less, you could use lithium ion battery. They are significantly quieter than any power supply regardless of cost, have no ripple, are not effected by mains noise, and cost less than $100.
There are a number available on eBay and Amazon that output 5v. All you’ll need extra is an adapter from USB to whatever plug the NF5x uses.