Gandi is free for a year and then expensive after - Namecheap may not be free but renewals and initial costs are much lower. StartSSL is free but revoke-ing costs money.
Revoking StartSSL is only $25. If you go 3 years without needing revocation then you're ahead of paying Namecheap or anyone else for basic domain validation.
just checked now, Gandi is 40€/yr, not that expensive compared to big names like Verisign & co.
I have used in the past RapidSSL, but it is same price, 50$/yr.
I've just checked Namecheap and it's reselling other SSL like Comodo or Geotrust, but it looks less expensive, so yes, probably it's the best price.
