I'm looking to buy/license an e-commerce system to sell a specialized product. This product requires the customer to put in from 3 to 12 detailed measurements, 4 other options. Once input the system will calculate a one-time price for this custom made item.
I've been looking at a slew of shopping carts and none of them appear to offer this type of configurability. I can figure out how to set-up a web page that gathers the data and applies the algorythms to calculate a price but then how does that get back into a shopping cart for payment and processing?
I'm not even sure how to describe this function for an effective internet search. I've limited resources and cash flow so I can't pay anyone for a bunch of custom programming.
Any ideas of how to approach this?

I tried setting up my own... nightmare. I use a super easy website that costs less than 20 bucks a month. It does Everything and has the most simple templates. I set up my site in 1/2 hour with my shopping catalog, photos, and all. Send me a private message and I'll give you more info.