>> google calendar like ... google calendar type features
to get a reasonable estimate from a good developer, the breakdown of the project needs to be very specific. define what you mean by "google calendar like" in terms of real identifiable features, like:
- authentication / log in
- user permissions?
- define what constitutes a work order
- does the system prevent conflicting/overlapping schedules
- alerts or notifications?
- daily views, monthly views, other views?
construct a wireframe of the interface, a hand-drawn sketch, with annotations describing the functionality you expect. That will help a lot. Then sit down with the developer and talk it through, and give them some time to come up with an estimate based on your requirements and their expected hourly rate.
I can't offer a ballpark price, since it depends enormously on the feature scope, who is building it, and the currency being paid, like whether it's an freelancer in NYC or an agency in India.
The price point may also affect whether the developer puts TLC into the interface to make it look slick, or if you're going to end up with a <table border="1">