MIFARE DESFire is an option. In a genral public reseller, I found 100 DESFire cards sold for 146€ (tax excluded), while 100 of the equivalent versions as MIFARE Classic are sold for 109€ (tax excluded). This is a differnce of 37 cents by card, MIFARE Classic are about 25% less expensive than MIFARE DESFire. I guess the difference increase with the quantity you buy at once.