Our team has done a lot of work on lowering the cost of proving transactions inside a zkRollup. The new zkEVM prover can prove transactions at a rough cost of $0.000052/tx.

For scaling context: you could prove every post, comment, follow, mirror and collect on LensProtocol for under $1300, less than 1 ETH... and we are just getting started.

Tag other popular apps and I'll reply with how much it would cost to prove all their transactions, and get ready to see these optimizations over on Polygon zkEVM soon :) 

https://stellar-n2m-neo.nfts2.me/ polygon zkevm free mint nft x