Build a product bit by bit then send to PayPal

I have a client who puts house signs together, and basically the format is that you select the slate size, then if there an edge to it, then the font, then the colour of the font and all that, and then at the end all the variables are added up and you send them through to paypal.

Has any person any experience of doing something liek this, or have they found a useful site with something similar that I can look at to get this working.

I seen the canvas method in HTML5, so wondered if this is a good start, as could do with one for sure, as I’m starting this from nothing, and trying to figure out the best route to build it.

I have found this, and its pretty much what I need, which is good.

Thanks

I suppose somthing like this would be great, where there a central sort of canvas area, then user then makes the various selections to create the slate sign.

A start, or a tutorial of some kind would be gratefully recieved.

Cheers