C E S A R is a fucking idiot. Don't trade with him. My Cash vouchers go for 60% or $300 for a $500 voucher.
C E S A R is obviously a retarded homeless slum dweller who buys these carded My Cash vouchers for $300 and re-sells them for $400.
Yes they are carded vouchers. Or they are obtained through malware/ransom-ware/tor-locker payments. These vouchers are dirty. Dirty money.
No one would sell real vouchers for $100 off. Stupid idiots like C E S A R buy these vouchers off blackhat forums are re-sell them.
My Cash voucher can and will be reversed and charged back if PayPal finds out they were carded. Your PayPal account will also be limited.
Either that or CESAR is money laundering as suggested by Tomatocage in Cesar's profile. Either way the only intelligent move here is to stay away from him.