We have a server based on free BSD, Apache. There are 2 shops now and will be more soon. One very custom and others on Zen cart. A lot of customization there done but needs more.
Using also SSL certificates from Go Daddy. Pay Pal and regular CC check out.
Job - regular service for all - activate alert software and provide additional addons piece by piece.
Provide backup and create back up - emergency running for the shops when main server is down.
Yearly contract, monthly payments. Addons by job - paid after all is running properly!