Reddit reviews Proguard Foam Hockey Puck 1oz | Soft and Lightweight Puck | Perfect for Indoor Hockey Games

Also if you live in an apartment or are a night owl with room mates, this foam puck - Works great on carpet and is basically completely silent. The downside of course is the weight is that it weights almost nothing and there's no tactile feedback so you don't get as good of practice, but you can shoot it, so there's a benefit there.

https://www.amazon.com/Pro-Guard-7093-Proguard-Foam/dp/B00AK1MN1S

at 1 ounce, the number of physical pucks doesn't change that much but weight is no longer a factor, as even 16,000 of them would be less than the payload capacity.