In one of my quieter moments, I have come up with an idea which should help. Here is a summary.

Thinking about it laterally, from the example you gave, you essentially sell one product, with some customisation options.

If you agree with this logic, read on…
(The following example covers number ranges in blocks of 100, with a provision for multiple ‘sets’ and different colors. Other options could be added as required, with corresponding changes being required to the cart object.)
The page with the add to cart form would appear quite simple, (better than my last post), but with the price being calculated on the fly, by multiplying the unit price of \$0.18 X the number quantity
You would need to add some columns and calculations to your cart object.
On your page, your add to cart form could have list boxes, where the customer would choose the startnumber and endnumber, a quantity field which relates to how many number ‘sets’ the customer needs, and a static list box for color.
Other 'customisables' could be treated similarly.

You would need to add the following columns to your cart object (2nd tab)…

Startnumber, endnumber and colour, all as unique, text fields
You may find it useful to add the following calculation to your cart object (3rd tab)…
NumberQuantity, whose calculation is ([endnumber]-[startnumber])+1, this is the total of individual race numbers , which you may want to display in your cart.
Price. The price would be calculated in a hidden field called \$ATC_itemPrice in your add to cart form.
This would be unit price (0.18) * Number Quantity, which is ([endnumber]-[startnumber]+1)
So, for example, for 3 sets of 201-400, you have \$0.18*200*3
Discount
A calculation based on the total value of the cart should work.
The calculation applied when subtotal price is >=\$xxx would be totalprice * 1/18, which gives a penny discount , setting the effective price to \$0.17 per unit.