Online Design Tool Recommendations

[Signs4Realtors]

I am looking for an online design tool that my clients can use to modify pre-designed real estate sign templates or create a custom sign design (for example, if someone orders a Coldwell Banker For Sale Sign, I want to show them a few standard layouts, let them chose the one they want and customize the template with their name, phone number, license number, etc.)

Can someone please suggest software that would help me accomplish this. I see inksoft.com and no-refresh.com when I search on google, but don't know anything about these systems. Thanks in advance!