AbleCommerce Shopping Cart Software

I have a product who's price is based on price grid.

The grid looks like this:
Product width on columns along the top with the product height as a row. The width and the height are in inches and most of the time vary by 6 inches.

How it works is like this:
1. Get the product width and the the products height
2. Go down the row until you find the height, round up to the nearest height if necessary
3. Go across until you find the width, round up if necessary
4. Read the price from the intersecting cell

Can this be down out of the box or would this be a customization thing?

I have been going through the online demo and the docs but I can't even find a place to start

You're describing the ability to mathematically construct various product choices. So the answer would be "No" it will not do it out-of-the-box based purely on mathematics.

What you probably want to look for is Variants and Options. You'll find it when you edit a product - it's on the leftside menu. Variants let you build a grid of combinations based on specific values. A good example is Shirts. You have 5 different sizes in 4 different colors. You're going to need a grid generated of each size in each different color for a total of 20 variations or "variants". Variants does all the hard work for you.

In your case, you could create a single product record with two variant options "Width" and "Height". For Width, you would specify the values like 6,12,18,24,30,36,42 and for Height you could specify 12,24,36,48,60. The software will automatically construct a grid for you with all the possible combinations of Width and Height. Then you can assign pricing and SKUs to each variant.

Play with variants for a while - they're really quite sophisticated