Founded in 2004, Really Simple Systems is one of the oldest CRM vendors in UK. Really Simple Systems offers three plans - free (2 users/100 accounts max), Premium ($15/user/mo) and Enterprise ($50/user/mo). Reviews for this CRM are overwhelmingly positive, though not as numerous as other popular solutions. If you are looking for a free Really Simple Systems alternative, need to have access to open source code or want to have a choice between cloud and self-hosted options, please consider Bitrix24.
* Please note that the information may have changed since the publication. For current prices and features please visit Bitrix24 pricing page.