From time to time I receive requests to evaluate a project and assess the initial effort (say, the first 6~12 months). This involves basically the platform and the team costs (usually the latter has more weight than the first).
As simple rule of thumb to quickly get to the point is identifying the three variables that every project has:
E) effort: a global indicator of the cost which basically takes into account: development time required by the technical staff, management time from the CEO, how many resources to involve and their seniority.
T) development time: how quick do you want your cake to be ready? Are in you in a hurry for X and Y reason? Or is this project a "side job" you want to invest some (but not too much) of your time for the moment?
Q) quality of the platform: do you want a scalable, distributed, bullet-proof cloud-based backend? Or you just need something "online" to showcase to VCs?
So, the client can have 2 of these variables, they choose which ones. The CTO (and the development team) has the other one.
Possible scenarios, as an example:
The client picks
Qand asks for a rock-solid platform (we don't want to rethink the platform again, do we?) in a short time because they have contacts with possible investors and don't want the lead to cool down. The development team then receives the
Evariable: that is, more effort on the project.
The client picks
Qas they only have this budget available at this time, but still would like a good platform: developers then receive
Tand choose to dedicate less time to the project and (for example) push forward other projects or go around with a bicycle chasing crows.
I'm sure other (more knowledgeable) people have written entire books about this little game of "the three variables" (can't detail too much in five sentences); however, sometimes you don't need to read books cover-to-cover about project management to learn how to start a conversation about a project with a prospect client and underline the basics.
Also, it will quickly raise a useful warning if the client does not want to play by these rules.