What are some alternatives?
When comparing Digicert and GlobalSign, you can also consider the following products
Let's Encrypt - Let’s Encrypt is a free, automated, and open certificate authority brought to you by the Internet Security Research Group (ISRG).
Comodo - Comodo, the leading Internet Security Provider offers Free Antivirus, SSL Certificate and other Internet Security related products with complete protection
VeriSign - VeriSign Authentication Services provides solutions that allow companies & consumers to engage...
AWS Certificate Manager - AWS Certificate Manager from Amazon Web Services (AWS)
GeoTrust - Guarantee online customer security with SSL certificates from GeoTrust. Purchase in bulk, manage multiple certificates & become your own Certificate Authority.
RapidSSL - Buy, switch and resell RapidSSL Certificates. Wildcard SSL Certificates also available from the leading data security software provider at low-cost.