TLD List - Compare Prices of All Top-Level Domains
Domcomp - No-nonsense domain price comparisons, updated daily
PorkBun - Porkbun is an amazingly awesome ICANN accredited domain name registrar based out of Portland, OR. We're different, we're easy, and we're affordable. Use us, you won't be sorry. If you don't use us we'll be sad, but we'll still love you.
Pricepeek - Compare prices of the same product across all Amazon locales
The Mac Index - Compare Apple product prices in different countries
NameSilo - Domain registration. That's it! And that's what makes it special.