Well theres planned to be 512 elite nodes.

At current usage, (it was 1k blocks per day average last month or so I cba to recount to average)

So lets average it at 1.5k blocks created over the blockchain at todays averages, lets keep conservative and say 2 transaction charges per block.

Thats 3000 transactions per day being charged 100XBY

Thats 300k XBY in total for the node network per day

300,000 / 512 = 585.9 ea

586XBY = $14.50 per day give or take.

Remember thats 24/7 not work days = $450 monthly

When the network picks up, the volumes will also be higher thus more transactions.

Edit: Im not 100% on what the consensus came to, but i think there was an agreement for 64% of the fees to be given back from the network to the dev fund for a few month or so when the nodes go live maybe someone else can clarify this for us!