1st and foremost, you will need a better set of photos than the one provided.
You will require orthogonal shots of each side that is at least 6 photos at high resolutions.
In addition, you will need to see each sides from an angle to get an idea of the depth of the detailing.
You can place the orthogonal images as a BG in the viewport and trace out a rough sqaure section polymodel of each side independent of each other.
You can later add more detail using polymodeling techniques.
Once all sides are done, you can align them in a box shape and attach them together and do some more polymodelling to finish the joined parts.
About the costing, that is very difficult to say. It all depends on your resource expenditure as discussed earlier, your profit margins, your hourly rate, no of hours required to do the job( This will vary from person to person depending on his/her skillsets). So you will have to take a call there.
Whatever you decide in terms of no. of hours required, make sure to add some buffer time. You never know, the machine may conk off halfway through or the internet service goes bust just when you want to send across the file to ur client and you may have to rush to another block/suburb to find a cyber cafe .
To my knowledge, the .stl format is a preferred format used to construct / print 3d moulds from actual 3d files. It stands for stereolithography. But u will have to check this with the client. 3dsmax does support export to .stl & .iges (which is another cad format popularly used by mechanical engineers)
This is the best I can help.
By the way, the reference photo looks more like a 3d render to me.. since the BG is very uniformly flat and even the perspective is very flat. If, indeed its a real photo from a real grill and the client has the grill with them, they will have no issues giving you multiple photos from all sides.. Without the additional images mentioned above, It will be almost impossible to come up with a precision model.
But what I would assume is that the client has picked up the image from some competitor and is trying to reverse engineer the grill by preparing a 3d model and making a mould out of it. But thats just my guess.
whew... Hope this helps..
