Business Cex.io vouchers?

Hello BHW, checking on who enjoys Cex.io vouchers. I mainly wanted the opinion on how much a voucher should co st depending on its amount per GHS. I do business with a few myself since I have quite a bit of GHS, mostly tho I give smaller .01GHs vouchers for ".05BTC", in your opinion, am I asking too much or to little? With the values, I am also putting the possible return for the person with longtime hold on the GHS, or the whole sale value for them, as I do have those that love to do just that... to each his own. What do you think? Has any made some successful business from it?