Hi,
We can make a comparison between sandy and MailChimp.
MailChimp is the more mature product. As a result, it has more features like: -
Email template designer, Split testing, Email Client Testing etc.
But price difference is huge, 1000 emails for 1 $ and 150 $ for MailChamp.
The only extra payment will be the hosting. Also the maintainance is a big task.
There is a company named "EasySandy", they provide all the features o be integrated with Sandy and provide backup solutions as well, they charge 19 $ monthly and 30$ setup charge.
I recommend to go for sandy and EasySandy. As it will be a tension-free environment for you.
Do let me know if you need my further assistance.
I am systems administrator with over 11 years of experience managing server infrastructures and data-center operations across multiple platforms (mostly Microsoft, partially Linux) mostly in virtualized environment (both Hyper-V and VMWARE). Effectively plan, install, configure and optimize the IT infrastructure to consistently achieve high availability and performance.
I will be glad to help you.