Preev is still not working as they supposed to work, so, alternatives like this one is needed
preev.com working, but there are certain problems with the SSL certificate. You probably have to accept the "risk" and continue on that site.https://preev.net/ always working, unfortunately, the planned improvements are long behind schedule
https://100bit.co.in is working as well, providing 10 years price comparison for 10 different currencies as an additional feature.